The ones that were more than once, were accidental silences, OR they spam. They are not out of control, The PLAYERS were out of control with the spamming.
Sometimes, people talking on Campus Chat are walled about what they said and it become a "words war". The person who posted may have bypassed and he got silenced for that. If it's not for a bypassing on wall, it may be an accident OR the person spammed and you just didn't saw it.