Sit-outs will continue to be a problem until the Poker sites (such as Titan Poker, Fair Poker, etc.) do something about it. It'd be nice if all of these sites handled the situation like Absolute Poker does (it's one of the reasons they're among my favorite poker sites I play at); to remove them after the first level of blinds.
I think it'll take a grass-roots approach from many of us players to let Titan Poker and the like know how we feel about this situation. I'm sure if they received thousands upon thousands of complaints, they'd have no choice but to modify their software to remove these players. Until that happens (or a major boycott is threatened), I don't see this issue going away anytime soon.