The rumor was that Cal South called some of the clubs that have U12 Development Academy teams and lots of 2006 boys on the list (e.g., Total Futbol Academy) and told them to please not bother to have their players attend if they were playing DA so Cal South could focus team selection on those players who would be eligible. Even among the kids who did attend, quite a few are likely to have DA offers, but just hadn't officially gotten word yet because some of the new DA clubs are still in tryouts and decided to come anyway. It's a US Soccer rule that the players cannot do both DA and ODP. Some of those DA or DA-likely kids didn't make the cutdown to 36, though, and I don't think it was because anyone tipped off the coaches that they are going DA. At the youngest age groups, DA isn't necessarily all the best kids either. It's the kids at or near DA clubs or with parents willing to drive far to take them to DA clubs.At the 06 Boys ODP tryouts many of those who were invited did not show because they were DA bound. There were roughly 65-70 boys in attendance. This was significantly less than the number invited out.
The list for the B06 appeared to be a "true" list, in the sense that they included tons of kids from DA clubs and didn't appear to exclude anyone ahead of time from scouting consideration.