All games (sports included) have some tactics and such that can give you an advantage. Day 31 players is one of those types of advantages. It's not like it's some big secret kept among an elite few...Thunder and Sunshineduck's guides spell it out pretty well, as do a lot of other threads. Half an hour of education via the forums isn't that big of an advantage. And it's not a big deal to arrange, either, at least not for a dedicated team.
The only potentially-valid argument I can think of is where an experienced crew of GMs decides to start a new Pee-Wee team, but because they have been playing higher level stuff for a while, they either don't know or don't remember how to optimize for Pee-Wee...and then they get beat by a less experienced team that has 55 day 31's. Does the less-experience team deserve to win? Well, does experience count more or less than 30 minutes of reading in two of the 5-or-less stickied threads in Pee-Wee? Would an experienced crew not do any research before starting up a serious Pee-Wee team?
Also, that scenario is almost irrelevant now. That could only happen in copper, and both teams would move up to silver anyway. And by then, the experienced team will have learned their lesson.
On top of that, Day 31 teams can get beat by better tactics and game planning, even if a team has far inferior builds.
I vote to leave the day 31 stuff the way it is.