Negotiating With Terrorists

Should you really never negotiate with Terrorists? It seems to me that there could be some pretty legitimate extenuating circumstances.

SITUATIONS I THINK MERIT NEGOTIATION:
1. You're buying a used car from a Terrorist. That seems like a perfectly reasonable time to negotiate. Is a Terrorist really going to kill six hostages because you want to pay 1000 dollars less than the Blue Book value?

2. You're at a restaurant with your wife, and you're facing the window, and there's a terrible glare off of someone's car window, and you notice a Terrorist has sunglasses on. Why not? He has sunglasses on. Maybe it depends on how friendly he looks, but it still seems like it's worth a shot.

3. You run an independent hardware store that's having trouble competing with the likes of Home Depot.