i think if AMD were to release a few leaks, it could help steer customers away from purchasing an 580 and waiting for caymen.
but honestly i doubt there will be enough 580s on the market to really make a big dent (we all know theres people out there who are buying both because they are flat out xtreme). and since caymen isnt too far away, the delay difference will not cause many sales to be lost. and its a high end part which makes up a very small chunk of the population

in the end, i dont think AMD will have many lost customers by doing nothing vs giving out every last detail.