Hello guys, I am new to the escort business so please bear with me.

why the guys are still seeing escorts while it's clearly illegal in the U.S.?"

SEEING an escort isn't illegal.  If I hire an escort to accompany me for an evening, maybe dinner, maybe just to have a stimulating convo with a smart, beautiful woman, that's perfectly legal.

Well... if it was in fact behind closed doors and between consenting adults... why would a judge even be concerned? lol

Are you a provider or a client? You're living here in the US right? So you have a profile on TER and you look on BP at escort ads but you're worried about the legality of prostitution? Do you want to be or be with an escort? I'm not understanding what kind of answer you're looking for or if you are even someone we should be corresponding with...

having sex isn't illegal, neither is being paid for my time. Lot's of people are paid for their time. and lots of people have sex... so unless you're telling the judge that you paid someone to have sex with them... how would anyone know?

Is this why guys are asking providers to lift up their shirt to see if they're wearing any hidden mics?  Otherwise what is the right way of doing it?

Well i've seen some reports of escorts wearing hidden mics or hidden cameras in the room and they could use that as evidence against you.

Because the law often stands in opposition to things people like doing and the desire to do those things outweighs their fear of getting caught.  I apologize if was meant as a sincere question, but your post gives off a bad vibe.  You seem like a half-assed troll or an incompetent narc.

But a true story:  several years ago I booked an hour with an FBSM provider who, according to her reviews, had a very limited menu. But she's gorgeous, her reviews were very positive, and something told me I had to meet her.  After about 30 minutes of a good but uneventful massage, she stopped, smiled and said, "The paid session is over."  And then we proceeded to go far beyond her published menu.  

But if clients do so, yes, that's why.