Most contracts have some type of gag order (not just for showbiz, but for company employees too), which run for the duration of the contract, and some for years after they expire..
Don't think she'll write anything nasty about others, because that would be pretty low, and would most likely ruin all chances of any company/artist ever trusting her again..
People write how she was great friends with the other girls, but how do you know? I do team teaching, so I joke around with the Japanese teachers in class, hold their hands while doing dances and crap like that, but I fuckin' dislike most of them.. It's just an act for the students..