2004striker: I hadn't seen that; but I had noticed that the NASA (formerly Silverbacks) U16G team got in although they didn't win premier as the Premier League South representative.
I don't know for a fact how it worked for either CESA or NASA, but here's a theory. Both CESA and NASA teams we're talking about finished third in RIIIPL-East and the two teams ahead of them got in by winning state championships or winning RIIIPL-East. So maybe (and just maybe, because I don't know) they were seeded in because of the strength of RIIIPL-East versus North and South who had teams that won state championships and RIIIPL victories. However, please note that this is just a guess.
