Hi,
When the commit which introduced the regression is known, why not
simply assign the bug to the committer? Surely, people do follow
regularly the bugs that are assigned to them, don't they?
In my opinion, all regressions should always be assigned to someone,
at all times. Either to the identified guilty party, or to a volunteer
or maintainer of that field, who is then responsible for identifying
the guilty party, or finding someone who accepts to do it. This sounds
like a reasonable way of making sure some regressions don't get
forgotten, doesn't it?