It doesn't take that many to affect ENY quite a bit when numbers are low.  Unfortunately anything they do is so easily circumvented I can understand why they don't bother.  Although I'd be curious to see how many of them are intentional waiting for perks vs people who got sidetracked.  Every once in a while I don't log out because I think I'll be back in ten and get sidetracked overnight.
Wiley.