That's the whole idea, it's a ceremony. Otherwise it's just a guy showing up somewhere. I don't know the protocol behind one-day contracts but it is certainly possible to do it in hockey even without a proviso in the CBA - just sign the guy and then mutually terminate his contract the next day.
As for Brodeur, it is clear all along that he saw the goalie market was flooded and his dream is to parachute into a Cup contender who has an injury with their starting goalie, steal the starting job away from whatever they're using, and then lead that team to a Cup. Although maybe that's not his ultimate goal - the fact that he's no longer giving interviews suggests hurt pride. I wonder if he would try to come back with a mediocre team and then try to leap frog from there to a good team at the deadline. Doesn't seem likely. I think there's a decent chance (~25%) he won't play again.
I don't even know if he cares about another cup. I think he wants 11 more wins.
Trading Ryder to Nashville, to play under Laviolette makes too much sense to not happen, no?
Probably the easiest way to start unloading the 2nd/3rd line RW logjam.
Forget about moving Ryder. This was a down year for him but it wasn't a total bottoming out like folks are claiming. Ryder still put up 18 goals despite having a long drought. He still managed to do okay with his job responsibility which is scoring goals. However of utmost significance is that Ryder is one of our few right handed shots.