I can understand why he's doing this. Anyone that loves to compete will want to do so until they simply cannot do it anymore.
Maybe Favre needs to take up a bowling league or something.
But seriously, I feel that the Packers need to take a really long look at what is best for the team today as well as tomorrow. If they really feel like Favre is their best chance to win today, how can they really say no? The flip side to that coin is that does a Favre comeback ruin Aaron Rodgers, or his/the Packers ability to succeed in the future?
Those are the questions that will decide this if Favre is really going to make a comeback. But I still firmly believe he'll remain retired. If he doesn't though, I think the Packers aren't necessarily going to discount it and refuse.