Seems to be such a hot-button item, but I've never been negatively affected by the lounge chair fuss. (RCL and Princess). We usually get to the solarium pool by 9-10:00 after a nice buffet breakfast, and flop out in a few lounges. Almost all of the 'premium' chairs fill by about that time, but I rarely see chairs with stuff in them and nobody around (pool, hot-tub, up at the poolside bar for a beverage). Clearing the occasional abuser wouldn't have made much of a difference on my cruises.
Later in the day at peak times I often see people show up and walk all around the poolside seating, frustrated that they cannot find a chair. Thing is, I can usually see open chairs set back a bit, but the latecomers want that perfect chair right at poolside. They have unrealistic expectations. Can you show up to a hot movie opening at the last minute and expect to have prime seating? No... you'll be down in the front row. If I show up at a peak time, I know I won't have one of the prime chairs, but I've never had to look around for more than a few minutes for seating.
My experience must be unique, because of my mostly morning sunning, or maybe its that I prefer the adult solarium pool, or maybe its my choice of cruiseline.... I guess it could be different on a spring break Carnival cruise around the main pool, but those are the cruises I avoid like the plague.