revision id format stability?

[Stephen J. Turnbull]

Chris Hecker writes:

 > I changed it to checker at machinename and it's okay...at least that 
 > differentiates between machines for me with the same account.  It yells 
 > if there isn't an @ sign in there (not the most robust email validation :).

Well, it's actually an idea that goes back to GNU Arch.  The point was
that your (valid) email address is a way to guarantee global
uniqueness of revids.