See, the funny thing is, we, as fans expect there to be contingency plans like that, but I think in this particular deal, with so many moving parts, and dealing with two teams, I don't think Charlotte and Milwaukee would have been interested in doing the deal if they had to deal with a contingency plan, so it could have been a scenario in which Petrie could have asked for something like that, but then there would also have been a good chance where one or both of the other teams would have balked on it, because then you'd have too many players publicly known to have been traded. How does Salmons return to Milwaukee if we get Brandon Knight, after it was reported on ESPN that he was going to Sacramento. What about Stephen Jackson? How are these players going to return to their teams, after it was so well known publicly? That's why I don't think most teams would agree to such contingencies, because the deals are too complicated, and each side needs to know if it's really going to happen. They can't deal with a last minute change that negates the whole thing.
But... I think Petrie needs to have such a contingency plan, and also needs to make sure the deal is totally secret until after the No.7 selection is made. Why did this have to leak so early? That was a huge mistake. Obviously, there wasn't any contingency plan, because otherwise it would't have leaked early. Petrie either didn't demand a contingency plan, or one of the other two teams balked about any contingency plan. Either way it was a mistake, because if one of the teams balked on it, then Petrie should have just backed out of the deal altogether.
If only we stayed in our shoes, and didn't try to get so cute...