I don't think you can cut the legs out from under a team in first place in July should that unexpected joy be presented to us. Still, if Hahn got offers he couldn't refuse, I think everyone would understand. He isn't going to get those for many players.
On the flip side, what do you do about acquiring players if they are in first place. I would hope they would be willing to acquire players where they are taking on salary but not trading a prospect.