<This is probably more correctly filed against postfix, but there is no entry
for postfix in bugzilla currently>

Upgrading to hampton beta1 from RH 7.x systems which have postfix fails with the
error:

useradd: user postfix exists
execution of %pre scriptlet from postfix-1.1.2-3 failed, exit status 9

install: %pre scriptlet failed (2), skipping postfix-1.1.2-3

this is probably because the RPM does an unconditional add of the user postfix,
rather than first checking for the existance of the postfix account.

Since RH did in the past ship postfix RPMs in powertools, this may pose problems.