I don't know what else you can do other than simply trust your gut.  I've been with a couple of women at an agency that was later busted for trafficking and I honestly never suspected a thing. In both cases they fucked my brains out and really appeared to be enjoying themselves.  Now, they may not have been trafficked at all but some of the gals at that agency were.

I've never felt that any indie I was seeing was doing anything that she didn't want to do but, as you say, there are no guarantees.  To be honest, lots of women who are NOT trafficked can behave as if they would rather not be alone in a room with you sometimes...

I don't want any part of part of human trafficking, especially involving underage girls. So I avoid AMPs and agencies for this very reason.  (Yes, I know there are some good agencies out there, so please don't make this thread about that.)

I like independent ladies who are in it all for themselves. In fact, most of the ladies I visit are under the radar, seeing just their regulars, and don't like being reviewed. Some have semi-retired, no advertising, but never deleted their old TER reviews.  So it isn't always easy getting an appointment if you haven't seen them before, but it still can be done.

However, just knowing the lady works independently is not fool proof when it comes to trafficking or coercion. So what can I do to ensure the lady behind the door is there of her own free will?

After I have chatted with the lady a bit upon first meeting her, I have been known to flat out ask her. For example, during the "get to know you" period before the real "action" begins. But even then they may not be truthful due to fear or coercion.

Is it even a good idea to ask that kind of question? Do providers get put-off or mad if someone asks?

What are the warning signs to look for?

As far as NYC is concerned, I think your impression of AMPs is way off base. At the many places I know about , the girls come and go, travel and return, make a ton of money (I am told) and blow it on shopping and having fun. They are well-to-do free spirits. Some of them actually do decide to go indy.

It's a no-win question. Frankly, all it can accomplish is to falsely soothe your conscience. I agree with BostonGuy that the best you can do is to trust your gut.

Like with a lot of questions relating to P4P, you can never have absolute certainty. There's a lot of gray area between coercion and less than full willingness. Many providers, if they had their choice, would rather be doing something else, but they're such good actresses that we'll never know. In the short time I've been mongering, I've seen several girls who seemed to have it all together suddenly fall under the influence of hard drugs or an abusive "boyfriend". Maybe they were actually being coerced when I saw them, but it just wasn't apparent yet.

If you stick with well-reviewed, reputable providers with a reputation for calling their own shots (or working for a rare agency with scruples), you improve your chances of never patronizing trafficked or pimped girls. But if you pay to play, you simply have to accept the fact that somewhere along the line, without knowing it, you may well have done exactly that.