I see it as they had removed the "continued mutual goodwill" from the equation, and were offering nothing additionally. (If my current employer asks me to sign

I see it as they had removed the "continued mutual goodwill" from the equation, and were offering nothing additionally. (If my current employer asks me to sign something without any additional incentive, I'm not going to say no without inspecting it, since our continued mutual goodwill is important to me.) That kinds of puts them into the same category as someone who comes up to you on the street and asks you to sign something. You don't owe them anything - there's no goodwill - there's no upside. They get "basic politeness" but not co-operation. Sure, it might not cost you anything to sign, but you'd at least need to spend the effort (or money for a lawyer) to ensure that.