sysvinit removed without installing upstart

[Jeffrey W. Baker]

I was just playing around with an Edgy system, dist-upgraded from
dapper, on amd64.  I noticed that it's quite possible to remove sysvinit
without installing upstart or another replacement.  Is that legit?  I
didn't bother trying to reboot my system in this intermediate state,
because experiences tells me there's no way it should boot.

Shouldn't something depend on sysvinit|upstart?

-jwb