Just read an interesting point by Grant Johnson over at Chief Marketer comparing the recent fall from grace of golf phenomenon Tiger Woods and the runaway acceleration of Toyota's perceived quality problems.
According to Johnson, both Tiger and Toyota committed the cardinal sin of reneging on brand credibility, and in response their customers have quit buying—or in Woods case buying into—their products. Interesting parallels here, as both brands had strong customer identification and were known for strict quality control and attention to detail (albeit in remarkably different contexts).
Crap happens, as the old saying goes, and Grant argues that the best prophylactic is to have a comprehensive PR plan poised for just such emergencies and a crisis management team ready to pounce (The case most often cited, and in fact cited here, is Johnson & Johnson's successful handling of the http://en.wikipedia.org/wiki/Chicago_Tylenol_murdersChicago Tylenol murders in which several people died after taking their product.)
Grant then takes the credibility argument even further, going on to argue that more proactive brands like Hyundai and Lands End (even GM is cited) have seen their sales rise recently because they've offered good old-fashioned money back guarantees to back up their brand promise with action, thereby increasing their brand credibility in the public eye -- and actually turning the iron-clad warranty into a branding asset rather than just an accrued liability.