Again, leaving every now and then is going to be fine.
Serial leavers are the ones who Blizzard is targeting. Are you a serial leaver? No? Didn’t think so. So the odds of you getting banned is extremely low.
Blizzard knows the mechanics to the fights they create. If they know that will wipe the group, and you keep doing it, then yeah, they’ll ban you for that. So if you want to get banned, by all means, be a douche to your group. That’ll fly as well as a balloon made out of solid steel.
Blizzard LITERALLY said this is who they were targeting with this change. You’re the one spinning this into a ‘but maybe’ fearmongering scenario.
It isn’t more clear than that.