The point is, The Izzi owner proposed this deal a looong time ago I'm assuming. Musky let it sit there just for the heck of it, even though he knew he wouldn't accept it under normal circumstances, which is a good idea. If something major were to happen to Gagne, he could go back and accept it to unload him for Izzi. Now that the deal had been sitting there for a while, Izzi's ready to come back, and Gagne isn't. Personally, I never decline trades in hopes to be in a situation somewhat like this lol.
If you know the guy fairly well, I would accept it just to get a rise out of him, and no harm done b/c u can just veto it after u have gotten his reaction haha