Well, here's the deal: the main reason that the decision was made to lock the threads until the lineups were posted was because I didn't want people to have the impression that x player was playing over y player and have three pages of stuff about that only to find out that those lineups were incorrect (until the official lineups are posted, I just go with the previous day's lineup). But come to think of it, regular season lineups don't differ much at all from day to day, so I suppose I could just leave the thread unlocked all day after I post it in the morning.
So basically what I'm saying is I have no real preference, to be honest, although if there was a way for me to get consistent lineups well before (at least two hours) the game, I would say that threads should be locked until lineups are posted. But looking at Chico's track record (my current source for lineups), I can't say that the lineups will be available with any consistency.