Idiot-with-a-cancelbot sounds like the most likely bet to me.
There have been repeated cancel attacks on *.answers from various bozos.
Ask about it in news.admin.net-abuse.usenet if you really want to know.
I think it mostly happens on weekends, thus FAQs posted on weekends are
more likely to get canceled. For instance, I post my own FAQ on
alternate Sundays, and for the past several months I've been noticing
that one or both parts frequently fail to arrive at rtfm. Since they're
more or less the same size and posted to the same newsgroups, it's
unlikely that deliberate filtering at an intervening site is the cause.
I've assumed that someone is canceling random articles in *.answers.
It's probably way too late to get any information on the Feb. 27
episode; I think most sites expire control messages in far less
than a week. But maybe it'd be a good idea for someone to set up
a filter to watch for cancels against *.answers articles?
(Chris Lewis, are you still reading this list?)
regards, tom lane