Suggestion!
I agree that this would be a pretty big problem.
To solve it, you need to convince people that updating their info, is worth it.
How do you do that, you ask?
Well start by contacting some big name teams, and convincing them to post info.
If you got teams like 67, 217, 111, 1114, 233, 190, 148, etc..
to have their information on your site, then many other teams will follow suit.
Also, if you contact people in charge of regionals/kick offs, and have them do things like, talk about about your site at kick off,
and send an email about it to all the teams competing at their regional.
Then im sure you would have plenty of teams on your site by the end of build season.
Again this is just an idea
My $0.02
Hope it helps.