The free market can regulate this just fine!
Very simply, any exchange which proves its reserves / liquidity, use them. Any exchange which does not, steer clear of them. The market itself will dictate which exchanges remain viable and which fall by the wayside. Any exchange which does not prove its reserves will suffer, thereby encouraging them to meet the standards set by the other exchanges which do or lose business to them, and the increased competition by exchanges constantly trying to become the most desirable for consumers will bring huge benefits to consumers.
Government regulation is never the answer, and usually has unforeseen consequences down the line with the laws implemented to "protect" consumers being used to strangle new enterprises and prosecute (or indeed persecute) others. Allowing the free market to self-regulate is always the better solution.
We can't stop government regulation, they are going to go forward with it regardless. At least we can say, "our advice is to do it this way, or it will never work".
They're sick and tired of sitting around not being able to do anything. Cash is flooding out and they're losing control. It's as simple as that.
A good example of this is "shorting a stock". While this is not illegal, most brokerages in the US are against this type of trading. Therefor, you resort to an overseas brokerage with "relaxed" feelings about this type of trading. The same applies for Bitcoin, exchange a) and exchange b).
Keep things at a state level and let each other country do its own thing. Don't jack an entire open-source project, that's mad.
This is worst than the US government asking companies to build back-doors in their projects. Insane.