Sure, I suppose if you are really dedicated you could play through a game in those 24 hours and get a refund to play for free, but that's a marginal enough case

Sure, I suppose if you are really dedicated you could play through a game in those 24 hours and get a refund to play for free, but that's a marginal enough case that it's probably not worth worrying about. I think your underestimating the number of gamers who would pull all-nighters to play through a game as fast as possible in order to play games for free. Heck, plenty of people already do that without the ability to get a refund once they are finished. Hell, if I was still in college I would seriously consider doing it as a broke student. Allowing for refunds within 24 hours is effectively a free 24 game rental for any game in the library.