So I would sit tight and keep a low profile.

If you are contacted, the golden rule is to refuse to say anything.

Then contact a lawyer and let them do the talking for you.

Here's hoping that everyone is safe during this.

(still not a lawyer)

Never admit you pay for sex!!

Best thing to do is never admit you pay for sex when you are question. Just tell them that you pay for a date or companionship because you were lonely or massage.  

LE may uses the man talk like "most men pay for it." Tell me if you pay for it. It sound like you pay for it.  Just tell them that you jack off in the morning and had no sexual desire. You only desire companionship or a back rub.  

If LE push you to answer more questions, then ask to speak to a lawyer.  

If LE notify you to come to the police station for questioning, then contact a lawyer immediately. You have a right to have a lawyer with you during questioning.  

They cannot prove you every pay for sex because they don't have you on camera or recorded. The transaction was not done with an undercover officer so the case is weak. If you admit it, then they can bust you based on your admission.  

It is possible for the escort to bear witness against you. Since it is a he said or she said, it is a weak case

This is my opinion only...

You didn't do anything illegal.  
You are also not a high profile person who anybody would be interested in investigating.  
A tabloid rag newspaper would not even be interested in investigating you.
Law enforcement is most likely not interested in finding out who you are.
The person who you would get in big trouble with if you ever get discovered is your spouse (if you have one).  That is where the trouble really comes from 90% of the time.

Your TER ID doesn't lead to your true identity.  Your Date-Check ID doesn't lead to your true identity either (presumably you didn't provide them with this info when you signed up).  If you did provide them with your true identity, I don't know for sure whether or not they would destroy this info after verifying you, but presumably they did.  Also if date-check ever gave up info like this to any law enforcement agency, word would get out, and they would be finished.  

As for gmail and your google voice number, and cell phone call records, and text messages in general, unless you have been living under a rock for the past month, you already know that the NSA has all of that info now, and they are going to be storing it in a new million square foot data center in Utah.  But as far as I know, this info is not being used to determine who is seeing hookers.  Unless of course they want to know which hookers Bin Laden has been texting.  

If you want my advice, log into your google voice account and delete all records of texts to this organization.  That way if you lose your phone and somebody finds it, they can't see a record of who you were texting recently.  

In the future, use a new web based email account for hobbying purposes only, and get a throw away cell phone from Wal Mart or something, pay for it with cash, and keep that cell phone hidden when not in use.  None of these two things should be associated to your name, address, real email address, real telephone number, or your credit card.  You will have more peace of mind in the future if you do things this way.  

As for your question about protecting yourself?  You can't undo sending text messages from your personal phone, you can't really wipe the slate clean, this info really is saved somewhere, and if some law enforcement agency really really really wants this info, they can get it.  But you can do things the proper way (anonymously) moving forward as I described above, so that you have peace of mind in the future.
 

Contacting a provider is NOT a crime!!

You can be contacting a provider for paid companionship and it is legal. I won't worry too much about you contacting a provider on TER, Datecheck, or other hobby website.

What is illegal is soliciting sex for pay.  If you mention about sex for pay over e-mail, text message, or other communication device, you should delete it immediately.  

You should contact a lawyer if you get questioned by LE. If they don't have you recorded in video or audio with an under cover cop, the case is weak as long as you don't admit to paying for sex.  

If you has been confronted with text message or e-mail you solicit sex for pay, there may be a defense. Since there is no proof that you act on the offer, then it is no proof you commit a crime. You can claim you were curious.  Just because you saw a provider that is not proof that you commit a crime. A good lawyer will get you off.  

Best policy is NEVER solicit sex for pay over the cell phone or e-mail. Going to see a provider is NOT a crime because escorts sell legal services like paid companionship. What makes it a crime is there is hard evidence you attempted or trade money for sexual services.

to most clients.

       The real question is whether LE will decide to prosecute some, or all of the client list and, if so, whether they have probable cause for an arrest warrant. The prosecution and arrest are usually disaster enough - you are not going to fight it unless you are really innocent. So if they do prosecute you, you most likely are going to plead, or seek a deferred prosecution agreement (ie John school).

        The answer to the first question is usually "no" and indeed the US atty for this area supposedly has a policy of not pursuing state law johns who have violated no other law. See Exhibit 1 (Elliott Spitzer). State LE may be a different story.  

       The exception - if you trade reviews for discounts. In this case, there is a new wrinkle in the press I have not seen before -allegations of posts made in support of the agency on review boards.  That is certainly troubling for many. If no reviews or post, however, you are not going to stand out from the crowd.

      Given that LE has so much low hanging fruit here- i.e, actual clients, it is hard to believe they would expend resources going after some one who simply made an appointment request. As long as the request is sex neutral, I don't see the request on its face to be an unlawful solicitation, although LE can always go the expert witness route to translate code. But that's such a long shot.  

I think you will be fine

If you are contacted by LE, you say NOTHING. You politely inform them that you would like to speak to an attorney before answering any questions. That is it. You may not want to hire a lawyer, but you are an idiot if you do not. If you can't afford a lawyer (if God forbid the situation arises) you can't afford to hobby.  

Anyone who tells you otherwise is either horribly misguided themselves, or even worse, trying to set you up. Don't be an idiot. LE may not be smarter than you, but they know MUCH more than you do about investigations and prosecutions, and you are a fool if you try to talk your way out of trouble (they love that).  

I doubt you have anything to worry about; but no one here can say for sure what could happen. It doesn't appear that you did anything illegal and I can't imagine LE going through any extraordinary efforts to catch you, when they probably have the names of people who have used the service a 100 times. I can't give any further advice, but if it were me I would get rid of anything electronic and delete the accounts used. Maybe even my TER account. Good luck.