[nomurrcy]

Another idea (sans - or in addition to a tax) to improve the signal / noise ratio of the markets: mandate that all B/Os put out there have a TTL of 5 seconds or until they are hit.

So if you Bid at X, you can't pull that bid 10 microseconds later. You can't quote stuff / probe with orders you never expect to get hit. You can't create the appearance of 'market depth' where none exists at all.

[T_S_]

Exactly. You are feeding false information into the system. Limiting the trading to epochs and holding orders levels the playing field.