Yeah, there are a lot of reasons to place a bid early as mentioned. People not being in front of their computers definitely makes sense. I do it from time to time because I live in Asia and the auctions happen in the middle of the night, and when I do it's usually a proxy bid with my max.
I often see bidding battles well in advance though, often over several days. I think people have fun bidding it up. I often see early bidders come back and bid again. I guess I'm just venting cause there's often names I'm watching that I wan that start getting bid up in advance raising the final price up in my opinion. It's frustrating. Part of the game I guess.