I think there's some confusion about FOSTA. That legislation allows police to pursue domain owners for the content on their domains, rather than only going after the personal individual who posted or uploaded the content. In the past it used to be that the registrant of a site wasn't liable if a user who visited the site posted or did something questionable. That has since changed, although the cops may have to prove the domain owner either allowed or didn't take steps to prevent the activity from taking place.
If a prosecutor thinks that a review is sufficient evidence to file charges against someone, then he's going to use that review in court regardless of whether FOSTA was ever even proposed into legislation, let alone signed into law. FOSTA has nothing to do with that, it would be whether the "review" has any evidentiary value.
In regards to reviews themselves... There are only two circumstances in which I typically post summaries. Sometimes if I've had a negative experience, I will share the information privately rather than publicly due to the potential for abuse by the offending provider.
The first scenario is when it's highly likely that I won't be seeing that particular person very often in the future. Think about it: if I didn't enjoy my time with that person, then why would I go back to them? And if I have a good experience, then the most probable reason I wouldn't see that person often is if our cities tend not to coincide.
It doesn't really matter if the appointment was positive or negative, it just depends on how often I anticipate seeing that person in the future. If it's never or only once a blue moon, then I'm more likely to write a synopsis.
If I'm seeing that person relatively often, then I would be shooting myself in the foot to post a summary. If I post something positive about a woman, then the summary is likely to pique the interest of those who read it. That's probably going to result in her appointment book filling up much faster. So now she has less appointments available during any given day, and I would have fight for a time slot to get in amongst the other people trying to book. Also, if she gets more requests than she can handle, that's probably going to insinuate a a possible rate increase; high demand and little supply. Doesn't seem like a very bright idea for the person posting the review...
The second scenario in which I consider posting a summary is if I have an incentive to do so.
On a side note, many times it can be difficult to authenticate a review as being accurate. While this isn't always the case, there are numerous fake reviews about retail establishments, hotels, restaurants, lawyers, etc...
I can't overstate the value of having a rapport with providers I know I can trust. While I am certainly open to the idea of meeting new ones, I know from past experience that it's also a daunting risk... When I see a provider I'm established with, I feel comfortable and at ease going into the appointment. When I see a new one I know I'm basically walking into Pandora's Box. If I receive an internal referral from someone I know, I might be less apprehensive about it. But online reviews aren't always the easiest source of information to rely on all of the time. It depends partly on being able to verify where they came from and the integrity of the person who wrote them.