You guys need to re-read my thread. On launch day I was able to reproduce the signal drop/crash on the VERY SAME phones I tested yesterday.
All of Apple's stores have microcells and thus strong signal. Furthermore, I can still signal crash my <own> phone in the Apple store. So logically, if I can signal crash my own phone then I should be able to crash Apple's demo units, right? Well not if Apple replaced them with units that aren't defective.
One of two things have happened: Apple has replaced these phones OR they're running an unknown firmware that fixes the issue.
I challenge your statement about all Apple stores having microcells. On one of my visits last week to service my 3GS, I asked the genius if they have the microcells in order to make the phones "look better". He asked me to look at my 3GS' signal strength. It was at 2 bars. The genius bar is always at the end of the store and has the worst reception. I looked back and asked if it's always like this and he nodded.
He said the staff there have suggested the idea but the store manager isn't OKAYing it because of the cost. Which is why all iPhones stay at the front of the store, where reception is more acceptable. I know you can say that it probably costs Apple nothing to do it from their standpoint but that doesn't mean that it's actually being implemented. I see no reason for the genius to lie to me on this one (although I have been lied to often by them). The bars spoke for themselves... though.