You are talking about the old "you are paying me for my time and nothing more, anything else that happens is a private matter between two consenting adults" statement, correct?

Ultimately, the statement itself means nothing.  It is standard boilerplate text, which in the eyes of many is supposed to absolve the monetary transaction of an illegality.  Regardless, if either party ever goes before a jury, this statement would mean nothing as every juror knows what you were really paying for.

Don't worry about that statement.  You'll either get everything you want with your donation or you'll end up paying more afterwards, depending on the provider.  Your best bet against getting stuck with the old upsell is reading a lady's reviews.

Of course, the accompyning phrases to look for are things like "no tipping required" or "all-inclusive".
But, as stated by another responder, nothing beats good, clear reviews.