They'd better.
I'm as surprised as you are (well, probably not because I'm not using S3, but I know a bit about how it is put together and I can't believe the Amazon people are happy about having this happen to them, it's the exact opposite of what should happen in a 'cloud' storage situation).
I think there will be some pretty high level meetings on this glitch, the one thing you don't want is customer data going absent-without-leave, even if only on a holiday instead of a permanent departure.
Isn't it against your instinct to have data from different customers live in what amounts to be the same file? I understand you've got it encrypted to the hilt but that seems 'un-Colinish' ;)