Common wisdom is that clients handle NOTICEs to messages VERY BADLY. Like, NEVER DO THIS. You can get banned from channels and networks for it.
Especially one claim in particular, clients will treat any NOTICE to a channel like a ping.
We should look into how clients treat notices, and notices to channels in particular. Whether they use a different appearance for them vs just displaying them like a normal privmsg, etc etc. It's definitely true that the original purpose of them ('a privmsg that bots don't respond to') is no longer accurate, but how not-accurate is it?