30 minutes free trials - your experiences and opinions?
 

I know that some sponsors are offering now 30 minutes free trials.
In generall, this idea seems interesting to me and with no doubt 30 minutes free trials are better than longer free trials - from the point of view of the paysite's owners and the whole industry at all.
However, I don't know how the 30 minutes free trials work exactly.
I guess the surfer has to enter his cc details for "age verification" :-) but he is not billed at all. But after the 30 minutes are over, is he billed automatically f.e $39.99 for the first month, if he didn't cancel the membership? Could someone precize this?
I've read somewhere that webmasters should avoid using the word "free" when promoting paysites ( even if one can join them really for free ), because surfers don't believe they are really free and won't join them because they're afraid someone is going to screw them over...
This was an article about TGP's, but I suppose thia can be true not only when it comes to promoting paysites on TGP's.
If f.e someone is searching through a pay-per-click SE for "teen sex" and within the results he gets, 95% of paysite's desciptions contain the price and eventually the trail period
( f.e. "Hot Teen Fucking - 3 days trial membership now only $2.99" ), if he see an ad like "Best Teen Sex Site - join now 100% for free with valid credit card", he may not join because he will get suspicious, that the membership isn't really free and he will be billed even more than $2.99. But if there's an ad like "Hot Teen Site - teenager sluts getting fucked in hardcore xxx movies - now you can get free access to this great site for 30 minutes" - the surfer won't see anything suspicious in that offer, and more likely he will join that site.
That is at least what I think but I may be wrong.
So can you share with me your experiences with honest sponsors that offer 30 minutes trials? How was you ratio compared with the ratio with sponsors with usual trials ( like $2.99 for 3 days ). If there's really any good sponsor that offers 30 ( or 60 ? ) minutes free trials and pays per sign up, I'will gladly sign up under your ref. ( maybe a screenshot of your stats? ).
But don't reply like "sign up to THIS SPONSOR - they pay $40 for 30 minutes free trial and convert like a motherfucka!", I'm looking for more detailed answers and opinions.

regards,
p_a