It can be a pain if the weather is great, but as the other respondent says beds are not supposed to be saved and staff also remove towels after 30 mins.
There are always inconsiderate chair hogs. If they have not appeared for 30mins then I just remove their towel and belongings and hand them to the pool staff to look after. There are signs everywhere asking people not to chair-hog.....I just enforce it.
YOU actually enforce it do you? I have seen passengers trying to enforce the rules and the arguments that follow are unbelievable. Not worth the hassle. There's always somewhere free.