iPhone 4 reception problems: Apple's fault or AT&T's?

So, Apple just put out an open letter to iPhone 4 owners (and a skeptical public) admitting that the iPhone 4 has reception issues.  Except, they claim the reception problem is not with a faulty antenna design, but rather a software flaw.  Specifically, they claim that their algorithm that determines how many "bars" of signal to display was flawed and over-estimated signal strength.  They say they'll release a software update "soon" to address the problem.

Honestly, such a claim baffles me, because I see no reason why they'd ever have to change that algorithm between versions of their iPhone operating system.  But that's neither her nor there.

From this scenario, there are two possible outcomes:

1. The software update works and iPhone 4 users are once again happy iLemmings.  
2. The software update does not work and people get their pitch forks ready for a trip to Cupertino.

Oddly enough, the first scenario interests me more.  What possible motivation could Apple have to over-estimate the signal strength of their phone?  As we've seen, signal issues tend to get blamed on the hardware unless people understand that the carrier is to blame.  And, as everybody knows, AT&T has a pretty poor track record of coverage.  

The only motivation I could see for this software "error" (if it indeed is the case) would be AT&T colluding with or bribing Apple to adjust their "bars" algorithm.  After all, AT&T centers their advertising campaigns around the number of "bars."  My friends and I always compare signal strength between carriers when somebody loses reception or drops a call.  Artificial inflation of signal strength would be a very powerful and effective direct marketing tactic.  It also sounds sooooo AT&T.