OPSEC is a process, but it is also a mindset and the process that identifies critical information to determine if friendly actions can be observed by enemy intelligence.

OPerational SECurity

It is absolutely ok to Pre-Screen with reputable providers.  This guy spent too much time watching Army movies.  I promise you it will only benefit you.  

OPSEC isn't just necessary for spy vs spy military stuff. This is going to be a long post, honestly, it's too long and I probably wouldn't read the whole thing myself, so if you'd like, skip to the bottom and get the sparknotes.  

 
If someone is thinking about replying to this because they don't like XYZ, they should understand that OPSEC is a complicated subject and I've tried to boil down what I think is important. This isn't exhaustive, nor complete in any way. I hope that you'll consider that at minimum your information can be used against you, and you should be taking steps to prevent it.

  The basic idea is that your information is valuable, but it's also a huge liability and at the worst times, it's a weapon. Pre-screening seems OK to someone casually evaluating things. If you take it a few steps further, it's obviously a bad idea. OPerational SECurity and INFOSEC, or information security, are closely tied together and you rarely have one without the other. Giving out information needlessly is very, very poor OPSEC because that info is now venerable. You can't protect something that you cannot control.

 
  The problem is, you can't trust that the person you're texting/emailing/calling is actually who they say they are. TER mitigates that issue, because multiple people are confirming that (555)555-5555 is actually an accurate number. Without TER, that risk is harder to mitigate. You have no way of telling if someone's been compromised, which is a very real possibility (although somewhat rare). You also have no way of telling if this 'pre-screen' information is being stored or not, or how a provider will verify you in the future.

  We've all heard stories about agencies getting rolled and their contact lists falling into LE's hands, which usually leads to guys getting rolled up and charged with "sex trafficking" or some related offence. Even though the truth is much more above board (we know this) the public perception of "sex trafficking" is underage women being kidnapped and sold into sex slavery. That's a hellofa stigma, which means it's a hellofa risk. Understanding risk is OPSEC 101. The possibility of an independent escort getting 'flipped' or otherwise forced to give up her contacts, is a very real one. If she's stored your personal information in cleartext, LE will have all of it. Once they have a few girls worth of information, they can start building relations between them and before long they'll have a solid network to do what they will.

  Most guys on this board are under the assumption that "they won't get flipped" or "don't have my data". This is provably false, but, it's unimportant because it's unnecessary to "flip" someone in 2018. LE can get into your average phone/email/bank account without any trouble, and without your knowledge or consent. SESTA isn't just about websites in the classical sense remember, it's about any "interactive computer service", which includes basically any communication in 2018. Your phone and all of the services on it are now fair game. We think of someone hacking our phone as getting at our contacts and text messages, but realistically we're talking about ANY data your phone provider has on you, which likely includes, backed up contacts, call history and metadata (likely everything that was said in text format), location data (GPS, WIFI, and tower info).
  To make this worse, they don't have to individually target any one provider, they can pull data in bulk, filter it to the "soft targets" and build relational databases with the data from there.

***To wrap this back around to pre-screening, there's one glaring flaw here. If most of the hobby goes to pre-screening, any given indie provider is a better target, and as a monger, you're expanding your attack surface much larger than it needs to be. You can't easily prove that you didn't see someone, and once LE has your information, you're a sitting duck.

  So, to answer your question, the right thing to do is keep your data safe, and require that others do the same. Here's a short list of the big stuff. This isn't exhaustive by any means.  

-If you have a private archive of contacts that you've screened, you need to either delete it or encrypt it with a strong password.    
-Practically a strong password is a long-ish sentence that isn't too general. "Veronica is awesome" is a bad password, "Veronica is an awesome lady" is so-so password, and "Veronica likes her starbucks iced on mondays" is a good password. You get the idea.  

-All of your client communication should be encrypted. (proton mail and signal messenger are good places to start)  

-Use a VPN like NordVPN that doesn't keep logs and is based somewhere with poor US extradition agreements.

-Don't give your info out unnecessarily. Make sure you aren't giving info away on accident.

-Make friends with other providers who see clients that are similar to yours.

**For guys looking to shield themselves from a TER shutdown

-Build a private database of providers you might want to see with contact info and pictures. This can be as simple as a password protected ZIP file with subfolders containing pictures and contact info. DO NOT USE A WEB SERVICE LIKE ONENOTE OR EVERNOTE.  

-Encourage the women you see to use encrypted forms of communication like signal and protonMail.  

-Use a VPN like NordVPN that doesn't keep logs and is based somewhere with poor US extradition agreements.

-Don't give your info out unnecessarily. Make sure you aren't giving info away on accident.

-Make friends with other mongers with similar tastes to you own.  

 
And finally, the biggest thing we can do together is to continue to be a help to each other. We're all in this together.