It may well -- would give us the ability to push it
onto other usergroups if
we need. The primary reason for using the global was that it's much more
clear *how* to disable email-blocking, as this is likely something that many
wikis will want to disable (at least, it's more clear than
$wgGroupPermissions['sysop']['blockemail'] = false;). Everyone I asked
about
it felt as indifferent about it as I did though -- how 'bout we make a
hybrid of the two? Have the global that will disable it regardless of who
has what rights and the right itself which is also needed to use it?
If you can't decide how to do something, let the user choose. It's
always seemed a good philosophy to me.