It's one of the concerns of people in the area - because its prevalence is hidden. Those sorts of people are often hidden pirates - people who rent DVDs/games and burn their own copies at home - hence once you break the seal (at least here) unless it's faulty, it's yours forever. Like the usual stories of women buying expensive clothes and returning them after they've worn them once.
This is how it is here, music/movies/games, anything on CD/DVD media once opened cannot be returned - only exchanged. If exchanging, they also remove the packaging so you cannot return it.