Asking "are you a cop" is literally worthless. Cops are explicitly allowed to lie.
Euphamisms like 'donation' or 'roses' or 'GFE' or 'full service' don't do crap. If you can understand them, they can, and it counts as legal attempt to contract for sex.
Hiding $ in an envelope, leaving it out and going to the bathroom, putting it in a book, all absurdly useless. If you and her can figure out its a transaction, so can they, and it counts.
LE check aka Feel Up? Well is you are a guy looking to avoid an undercover sting with a Lady Cop... touching her might, emphasis on MIGHT help. Most places entering the room gets you busted, who cares if you walk later, the arrest and emberassment and hassle of a trial are the punishment. BUT...if it is a jurisdiction where they require a bit of evidence of intent to commit a crime, well, Lady Cops don't want yucky perp guys touching them, so they would not allow it. Esp in an intimate location. You need to ask, or the charge could be assault. But a Lady Cop will never say yes to "can I touch your chest?". If you say nothing, not even a mumbled 'uh-huh' to anything that sounds like a proposition of sex for money, such as "here for the GFE (or other euphemism)" then you MIGHT skate.
Some locales have laws criminalizing visiting a bawdy house, avoiding their need to prove an actual attempt to exchange money for sex. Just visiting does it. Others have explicitly made the LE check itself, the touching to evade law enforcement, a crime.
Cops aren't dumb, District Attorneys aren't dumb, Judges aren't dumb, little cute games don't fool them.
And just getting arrested is 95% of the punishment, even if all charges were dropped.
Only way to be safe is DO NOT end up in a room with a cop.