I'm pretty sure they said they were going to downgrade the pick from the get go or am I thinking of the Aker deal?
From my memory of it, we had an agreement with Adelaide whereby we would give the lowest ranking second round pick to Adelaide for Hudson. The reason for this is that we had another trade on the go(can't remember which player) and so it was possible that we could have two second round picks(both reasonably high in the order). So Adelaide are thinking that no matter what happens they will get a high second round pick for Hudson.
Unbeknowns to Rendell(who was new in the position) we do a last minute swifty, and take advantage of the new exchange rule whereby you can exchange picks for picks. We downgrade our second rounder pick for West Coasts(it doesn't affect us as we are trading it to Adelaide anyway) and we pick up an extra third round pick in the process(Sam Reid?). That was my recollection of it, but I could be wrong.
Adelaide was really dudded in that deal because of the last minute exchange we did with West coast, but in some ways it was their own fault for not dotting the i's and crossing the t's. Rendell didn't envisage that Scott Clayton would do that(they are good friends having played football together at Fitzroy) and wasn't really aware of the rule.
So, the exchange that happened with west coast was a combination of Rendells naivety and Scott Claytons rat cunning.
Depending on what side of the fence you sit, it was either pure genius or unethical. It was a great deal for us but it is not going to win us(Or Scotty Clayton with GC17) too many credits with Adelaide in the future if we want a trade badly.