I agree with Utz. One AM division and maybe a rec division for new players would solve this problem. I played in the Afternoon D-Lite a few years ago and the divisions were Pro-1, Pro-2, Advanced, Intermediate, Masters, Rec, Jrs, and Women. At the time, I had only played in 2 tournaments as Intermediate and was ready to move up to Advanced. So that's what I played, but I should have played Pro-2 since it was unsanctioned and there many more players in that division. Plus, I would have finished 2nd in Pro-2 and won more. Back then, I didn't know the difference between sanctioned or unsanctioned or why it mattered. I think part of the issue with this and similar tournaments is that several normally Advanced level players (in PDGA sanctioned events) moved up to play Open since it was un-sanctioned. Also, I think the number of players in each division can influence it, especially if someone is borderline Intermediate to Advanced to player. Or it could be a group of guys of similar level all want to play and compete together in the same division. But really who cares?
Do you know what breeds winning? More winning!