A bit like Bug 2044 but not the same: blocked registered users should get a
similar red warning to "you have new messages" telling them that they're bloced,
and should not accidentally try to edit.
So far I wasn't able to find logical reasons against this feature, but if
there's one, I am open to hear about it.
Technical questions another matter, as it may be debated that cache would care
(registered users have different pages anyway), whether lookup is feasible
(autblocking requires that lookup anyway), etc., I listen to them too.
Basic problem is that Wikipedia should not be Evil, and autoblock people because
they accidentally press edit link forgetting that their block is not raised till
the next hour (or even more sucky when they get screwed by Bug 856 ...)