i've always laughed when people tell me they carry a spare quick link without a chain too, chains almost never fail in such a way they you dont have to remove a pin to use the link.

that said, i dont ever carry a chain tool, knock on wood, i never had a chain failure on the road. i try and replace chains well before they are at the failure point.

on every ride i go i throw my money clip in my jersey pocket with my cell, it has my drivers license, CC, and usually at least a few bucks, for just this situation, gatorade, bottled water, you never know what you're going to need, and a few bills is easy to have on you.