After reading through all of the mystery surrounding Lafontaine's departure, I suddenly had an idea:
What if Patty made a serious mistake (which even good people do from time to time), something so serious that an immediate termination was warranted. Moreover, because the error was so egregious and embarrassing, either Lafontaine, the Sabres, or both parties, desired a confidentiality agreement signed in order to protect all parties.
What kind of mistake would warrant this? What kind of mistake would warrant immediate termination, and a mutual muzzling of all parties?
A possibility: an affair with another man's wife in the organization. Once discovered, Patty would want it hushed to protect his reputation, if not his marriage. The organization would want it hushed to protect itself from having its name tarnished. And the other man would want to protect his name, as well as perhaps that of his wife.
Just a shot in the dark, but it seems plausible to me.