I realize that this has probably been discussed before and I did a search, but here goes:

If I met someone attractive, say in a vegas bar, and she suggested going to my room and having fun, then a few sentences later she said that she was short on cash and could use some help.  Or she said she would spend some time with me if I help out with some cash.  Would this be enough to defend myself against charges?  What if I explicitly said I had no expectations except just to hang out? (better risk a chick walking off with cash and no fun than the alternatives)

you probably wont find a vegas hotel bar sting
they have too much invested in protecting their guests...

Why engage in such risky behavior when TER is here with reviews of many great gals?

To answer your question, I doubt if LE will give a damn what you say once some money is flashed.  You'll be wearing steel bracelets, for sure.

(still not a lawyer)

Unless you find yourself in a bar at 4 am in Vegas. But even then, I'd wait until I could do some TER research. BTW the other post is not accurate. Metro PD does in fact do stings with female LE in the bars of casinos. Search the LV board and you'll see.

I've only lived in Vegas for 19 years and have only been reading the Vegas board for a couple of years, but I've NEVER heard of Metro Vice targeting tourists with a female posing as a hooker in a hotel bar. Its bad for the tourist trade, after all! Usually they work a street corner/motel sting and get a high volume of arrests.
Could it happen? Sure.  I'm saying its not common.

MVR

I have read that about 40% of escort appointments in NYC do not involve sex.  I have met two women that I ended up just having conversations with (I know that might sound deviant) and I am sure that it happens.  Obviously paying someone to spend time with you is not illegal.  If I responded to an ad that was pretty suggestive or explicit (i.e. states that it would be a GFE) it would be implied that this is what I was paying for.  But, if I truly just wanted to "hang out" with someone attractive and maybe have them strip and dance, I am pretty sure it would be ok to pay them (correct me if I am wrong).  

If I met someone in a bar or responded to an ad that just stated, "Hi there. If you're an older gentleman looking for an unforgettable evening, I'm the girl for you," and either of us suggested we go to my room and they asked for $$ to help them out, would that be illegal?  Would that be grounds for an arrest?

What about if I explicitly state that sex is not expected (I am willing to pay for companionship without sex)?

will be wearing bracelets pretty soon.

As far an stating that sex is not expected, I suppose you could give it a shot, but the moment that anyone bares some forbidden flesh or otherwise engages in some sexual activity, the bets are off again.

On the other hand if you spend a whole hour with a comely looking cop discussing your kids and how nice the weather has been, are you going to be very happy?  I don't think so.

(still not a lawyer)