In our company we have several projects that are used in their subversion integration to have hook scripts that check the commit-comment to contain a jira-issue-id, some people "extended" them to make a specific jira-issue-id prefix as requirement.
As git uses on "server" side only push/pull methods maybe stash should be able to check the commit comments that differ from it's repository version to have jira-id's referenced and if not deny the push...
Anyway this case must be thought of precisely but my feature request may be clear now:

Please provide a way to require the git repositories hosted by STASH to contain a Jira-ID in it's commit comments. This feature shall be configurable per Repository (or Branch...)

We maybe can discuss the details here hopefully we can find a common sense to implement this feature request.