Now, if you wanted to needlessly increase complexity, give owners a switch to set their global/list preference to create a setting during a random time frame which they must manually set and reset. I wouldn't... but you're the Captain.
Oooh, I like this. I think tying this to a randomly generated hashtag would also be good. Also, the randomly generated hashtag would often be composed of swear words in the group's native language. :-)
Ahem. Please continue to give me feedback on the new notifications.