Fair enough.

> You don't want to force them into signing anything,

Actually, you do. The more you give the employee a chance to mull over the whole thing, the more likely they are to lawyer up and hit you with a wrongful termination lawsuit. As the employer, I'd go one step further and if the CFO has allowed for a severance package of n dollars, I would initially offer them 90% of n if they sign right away and if they don't, give them the full n. Anything to get things settled right here, right now, in the room.