If it isn't illegal, or the exchanges get away with it anyway, I strongly recommend folks do with exchanges as I do with banks: refuse to do business with them at all.

Citi stole from me, and the legal system enabled them to do it.  As a result I am now aware that banks are vectors for thievery, and I don't put money in them.  I never ever, will again.  

Don't do busines with a thief or a liar, or you will lose money.