I'd not be very comfortable with it because marking allies can sometimes be incredibly useful, notably for PLD's Guardian.
I'd just like their GMs to actually do something about it to begin with. I have a single example in mind of a player on Light that is consistently ignore mark spamming everybody in their team when they lose, and that emote over corpses over and over, and it's been like this for months and they're still playing there and pulling the same antics.