Earlier quoted context omitted.
There is already regulation governing the minimum pricing increment ("tick size") for financial instruments. It would not take to great a stretch of the imagination to imagine regulation covering the maximum frequency at which trades could occur. We would have to decide what sort of delay we consider tolerable, then (perhaps) hold auctions at that frequency - perhaps once per millisecond, perhaps once per minute, may…
Tick size is exactly the problem! Tick size means that sales go to the people with the fastest computers, not people offering the best prices.
I agree ... although chasing billionths-of-a-cent margins seems pretty pointless too. It is a good thing that there are lots of other options: Stochastic matching? Auction over order-book?