in my opinion this could make the idea of "a scheduled xhb" feel less reliable, and people get pings on chat and possibly even plan their day around knowing a scheduled xhb is on its way. is one getting cancelled a big deal in practice? maybe not but if it happened to you once you'd probably think about it every time after that, lol
then again, it's not much different than admins being able to offset xhb start time, in that way. and we already have that
maybe as a last resort or as an admin-assisted feature?
dunno, not opposed to it necessarily, but i think it's fine for hosting to be a commitment and at least the time can be shifted around by admins in the event of a conflict