Why would anyone do that?
Yifu seemed to have a fairly high opinion of ASICMINER. I do also. Their 130nm chips strikes me as the most impressive. Avalon's 110nm second, and the supposedly 65nm one being pawned by BFL is either not 65nm, or is a steaming little piece of shit. Or both. I'd certainly be writing this into any escrow agreement although it doesn't actually matter exactly why it sucks so badly I suppose.
If BFL is going to go with 100% escrow, I would say there is a damn good chance that whatever they deliver would otherwise be thrown into the dumpster.