UNIX doesn't define semantics for what happens when you lose power
mid-write. That means that what a filesystem does when that happens is a
quality-of-implementation issue: but given that power supplies are not
perfectly reliable it's a fairly important one, especially in countries
like the USA with a third-world electricity distribution network (as a UK
resident I'm privileged to have a fairly reliable power supply and the
most badass electrical regulations on earth: it's one of the few things
the UK's done right infrastructure-wise).
However, I'm afraid I consider 'files you were writing right now might be
chewed up' to be a *lot* better than 'files you were writing right now
might be chewed up, oh, and so might anything else on your disk, even if
you haven't touched it for months'.
I too saw this behaviour when I used XFS (years ago now): I've never seen
it using ext2 or ext3, even when I had multiple consecutive power cuts
during a lightning storm, even when I had bad RAM on the machine and was
doing massive cross-filesystem renames. Of course this too is 'anecdotal':
all reports from third parties are necessarily anecdotal. I don't see how
this makes them invalid (if they come from multiple sources).