They wouldn’t, but they might still be considered to be running an exchange if they keep a centralized orderbook. So i don’t know how they will get around that.
ShapeShift has never had an order book.
I just think the law will either be changed or re-interpreted to not allow this. Too great a potential for use in laundering money/tax evasion on capital gains.
If they don't handle any money, how do they make money?