There are a variety of reasons why LE isn't wanting time on SA.
1.The hit rate for any SB is low in most cities. You would need a smoking hot female cop for the job as the SD's usually say no if the pics don't match on the date.
2. They can't control the situation. Cops get johns at hotels with other cops in the next room. SD's pick the restaurant and then the hotel. No cop is going to risk all of that for a weak prostitution bust, alone.
3. What illegal has actually occurred? The couple met on a website, had coffee or dinner and then decided to have sex. The lady need some cab fare home. Cops bust johns before sex, SD's pay after sex.
4. I could be wrong. There are some LE's obsessed with prostitution. But assuming they find an SD dumb enough to skip the meet and just come to a hotel for sex with $$$ in an envelope, they might get a good bust. After many, many hours of time wasted. For the normal SD first or second date, there is just too much time and too many variables for most LE to even bother.
So stick with some rules.
Try to never discuss money over email. You can always say the amount will vary depending on how well we click.
Always meet at a public place first. Take your time and have dinner and at least two drinks. (if you SB won't drink, you might have a clue. If they down three martini's they definitely aren't LE!) If the girl is a cop, you'll probably figure it out and be able to split. If you are unsure, set a second date. LE will want to get to the bust ASAP. Most SB's are good with waiting to have sex.
Only pay after sex. I don't set a price beforehand and I have found that most girls are OK with this. I had one ask if we had an understanding. I said yes and she jumped on my dick. Female LE will not fuck you, male LE has been known to.
Most departments have tight budgets. Street Prostitution is what they focus on, then the hotel girls (often reported by hotel security, no hotel reports a couple showing up together for a fuck session). SA would be a very low bang for the bucks invested and I don't see any good busts coming from a normal SD/SB relationship. Do you ever give your wife or GF money? Is that only for sex?