For government to have gone after some certain business, then there is something fishy about their activities in my opinion to have attracted such attention which is not known to the public. As to whether Binance or Bitmex is the next, there is no saying for sure although its going to be a fact that they also have their files with the authority. Best way, don't keep the bulk of your funds on exchange sites because you will not be notified when the take down is going to happen and the first thing they will do is to suspend all withdrawals. When you fund is there, you end up being at their mercy which you might not be able to recover especially if you happen to be a US citizen and don't also forget that those exchange sites have implemented their own KYC and all of this they will be forced to turn over to government just by the show of warrant.
You wont really have any choice when they do start to hold up or freeze withdrawals and for sure you are aware on what would happen next when they find out that you are evading such responsibility.
Im expecting already that more exchangers would be easily be seized surprisingly if they would able to find a hole.