Margin trading is safe for the exchange if it works as usually described in the terms: they just act as a bookmaker reallocating customer funds according to whi

Margin trading is safe for the exchange if it works as usually described in the terms: they just act as a bookmaker reallocating customer funds according to which side wins each peer to peer bet. There's usually rules that describe what happens in gaps, closing the winning side with a win that never exceeds what the losing side put down when opening the bet. If they steal customer funds, then all is off, but same when there is no margin trading involved.