Why they shouldn't run, people like owner of Cryptsy is free , God only knows where, so BTC-E can just do that, move to some forgotten island, and then claim we got hacked. Pretty much is the same exit scam used by almost every exchange so far, Mt.Gox, Cryptsy etc.
how about poloniex..? someday ago poloniex get DDOS attack too, but today poloniex run smoothly without any problem, i think not all exchanger will run out.