Removing "Reply All" Functionality for Outlook Users Who Participate in Reply-All Storms, via Group Policy: what to do

In our org, we have halted these reply to all storms by simply setting up a Transport rule that looks for the specific subject of the email thread. We actually leave a transport rule ready to enable for this purpose, so to enact once a storm has started, just edit existing transport rule, modify the subject string, and then enable it. Let it run for a day or two, and then disable it again. If you are worried about blocking mail that you should not, just set the action to discard and BC a temp mailbox so you can review all the messages that you prevented from getting to the recipients. Also allows you a quick count of how many messages you stopped by dropping them all into a new mailbox.
Only down side is you have to be in a storm and know about it to get it shut down with the rule.
Thanks
E.R.