I've read many threads about this sort of behavior and it's very interesting. The last time I saved Seats or a place in line was back in Jr. High. I don't go for saving seats unless it's for a spouse or child. I don't mind being confrontational. It irritates me when I 2nd in line and I can't get a front row seat because they are all saved. If the person doesn't like it, what's the worst that can happen. Report me to the Cruiseline police.
As long as those types of people don't "mark " their territory, no saves for me. My dog found a couple ways to mark his favorite seat and I don't go near it.