I have Tin foil hats for sale..LOL
I think if anything, they are using the same testers from the first two batches, maybe they found some issues they would like to fix before a large influx of new testers, plus the last interview I seen from the dev's said at that time plans were to ramp up beta over the summer, with E3 and Gamescon coming up, I would not be surprised if part of the news is more beta invites, plus we do not know how thigngs are going how many people were in the invites plus friends and family, I hope they are getting a lot done.. As far as the leaked video, they have to to expect things like that to happen, not sure if it has anything to do with how they are doing beta, but i kinda doubt it..