I don't know if they are making fake screen names or not, they could just be loyal customers or people that are given clips for free for a good review.
But I do agree with you that A LOT of clips that seem to be getting comments are really not that good at all. I would wager to say that 70-80% of clips nowadays are of cute models forcing laughter. And I understand no producers are making it up when they say they have "genuinely ticklish" women, but from what I can see from videos the girls maybe ticklish, just enough it seems, but the vast majority of them are forcing the laughter rather than laughing from the tickling alone.
Unfortunately there is a glut of material out there now, but let me temper that with it is certainly better than the days of barely any material, and with that the competition for our dollars is getting harder so all the producers are trying more and more things. I have even seen video's with models (I will not say the company now, but they are a bigger name producer) that I have seen on a foot fetish site where the models feet are played with, teased, licked, nibbled on with out laughing, she smirked...smiled and it did tickle her but not enough to make her laugh, this model even said during...."Yeah it tickles but it feels good, it really doesn't make me laugh" yet she is on a tickling video and laughing like crazy.
Eventually there will be a non-biased review source for tickling material available. I am working with a few other members that watch all kinds of clips and we are working on a rating system and starting a yahoo group or even some threads here with an actual rating system. If anyone else is interested in helping with this project, feel free to PM me. Myself and a few others have seen this need for a while and just working on wanting to do something more than, "what a great video", and actual rating type system.
Rob