When meeting a provider for the first time, what should you say (or not say) to confirm they are not LE?
In other words, what can or should the hobbyist say that would not be self incriminating and allow them to turn around and leave if the answer is not correct or lacking?  Can the provider prove they are not LE by saying something or doing something that they could absolutely not do if they were LE

In a lot of cases if you go into the room, she will have you go into a bathroom where you get arrested. Or if you come in the room and prices are talked about, it is time get up an leave. In the same state I have heard of reports by 2 different county's use these techniques.  

In the 2nd technique guys who left were not arrested. In the other technique everyone who came into the room was arrested.

It is best to stick with reviewed providers from known trusted reviewers to avoid trouble. That does not always keep you out of trouble. Sometimes an incall location/hotel room/apartment etc can be hot with LE watching the traffic. When you come out of the room they will start questioning you. Remember to know your rights to remain silent. Just say you were visiting a friend.  

In most of the cases with arrests for prostitution people get into trouble because they tell LE they broke the law, by admitting they paid for sex.

How about - "Lets get naked and cuddle" (nothing illegal and LE women will not.)

If not as bold how about "here is the money for an hour of your companionship"

Nothing illegal more like the booming sugar daddy/baby relationships booming at colleges for gals to earn money for Univ.  Just like any dating relationships and on TV interviews agreed sex may be the prime goal, but your not paying for sex only for time in a "relationship".  

The games played in the U.S. when in most of the world can just hire a in private consenting adult sexworker and no big deal or legal issue.

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If you are in the room, they bust you. But there are things you can do to make it harder to prosecute.  

1) Make no reference to sex, or sexual acts. A popular LE trick is to get you to admit you need a condom, which implies sex.
2) make no reference to an ad or website that makes it clear or even hints that the provider is an escort.  

3) Only make reference to legal acts. "Why don't we start with a massage."

4) at any reference by them to sex for money (including condoms) make it clear that isn't what you wanted, and try to leave.  

 
5) if they bust you, don't talk and get a lawyer. Don't make excuses. Don't lie. Just shut up except to ask for a lawyer.  

And of course, see well reviewed providers who screen to massively reduce the risk that she is a cop or working with them. And avoid providers with new ads on Backpage, with no history.  

If you are not sure, you can ask the escort to join you for a dinner date or shopping. This will allow you to get to know the escort.  You can ask if they will join you at a hotel room to watch movies in the date. Never mention about sex because they can arrest you for public solicitation.  

The second option is ask on the phone if they do massage. If they say yes, show up at the hotel room. Pay them for massage and get a real massage. Don't make or accept any offer for 30 minutes. If there is an undercover cop, they will ask you if you want extra upfront. Never accept extra offers. Just stick to massage. After 30 minutes, what ever happens will happens

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If you fondle or manipulate the genitals, anus or female breast, you have engaged in sexual contact

Yes but that does not have to be included in cuddling - have you heard of cuddle parties?  There is none of this and totally legal.

If you say that, you can get arrested in most state for manifesting the intention to commit prostitution. A better line is "let's watch movies."  Any reference to touching, taking off clothes, sex, etc. will get you into trouble.  

For girls you don't know well (1) Dinner date (2) ask them to come to you.  

                                                                                                                           

There are cuddling services and it is legal. Don't ask her to take off the clothes or fondle you. It depends on how you word it. You can ask about it over the phone. It is not illegal. An undercover cop may try to ask if you want the clothes off or fondling. You should tell them "NO."  

Maybe latter into the cuddling you can move to another act.

You can ask, they can lie!  Anyone who tells you different is a fool and if you believe them, shame on you.  There is no sure way to identify LE until they bust you.  Screening helps, but not 100%.  So always keep it in mind that there is always a risk, no matter how small!  Hey, I like that so I'll repeat it, "there is always a risk, no matter how small".  Maybe someone will remember that phrase.