Not ZERO, but very low. I further agree with fish (we're on a roll here) that I too would not have recommended this as a way to book with a provider, but nothing that you have said so far jumps out at me as DANGER WILL ROBINSON!!!
IMHO, you are most likely going to get "more or less" what you paid for at worst, but please let me repeat, "This is NOT how to book a provider" and yes you are taking more risk than you should be, both from a LE perspective (low) and the perspective of getting a mediocre or lousy session (high).
A word of advice "just in case" she is a cop, do not hand her or even mention the donation or overtly talk about sex and do not answer any questions about "what would you like to do baby?" in actual words. Leave the donation out in plain site, follow her lead where it comes to sex, or if she asks you "what would you like to do?" Do not answer in words, simply go up to her and kiss her. If she is genuine she will kiss you back, in the unlikely event that she is a cop she will pull back and try to get you to say out loud (for the microphone) that you expect sex for your money.
There is really no such thing as an "LE check" but there are things you can do to make a conviction unlikely, Saying something dumb like "I thought I was paying you to have sex with me" would pretty much insure a conviction if you ever end up in the same room as a cop. Asking "can I kiss you?" without a mention about money will give you a lot of wiggle room if the cops were to burst into your room if that is ALL you said.
I am sure all this advice about how to conduct yourself is moot, as it is HIGHLY unlikely this is a sting, but in the future, please stick to "well reviewed" providers and you won't have to stress about it.