The reason why it's considered a high-risk site is probably because of their policy on freezing accounts and restoring them: the former they do on a whim (and in fact their employees are apparently instructed to find excuses to do so), and as far as the latter goes they have NO appeal process and even refuse to inform their customers why the account was frozen in the first place.
Accounts can be frozen if your address or phone belonged to a "suspect" user, it you made any transactions with one of such users, if your name is similar to one of theirs and so on.