We sorta don't understand the appeal to a fast food chain of giving away free food. They've already got the market saturation they need, their food should for the most part already be free anyway, and by always carrying the caveat "valid at participating restaurants only," (which they always say) they expose themselves to the possibility of many many very angry people.
Exhibit A: Popeye's last April. The fried chicken chain was offering eight pieces for $4.99, and the poor Lake St. restaurant, which wasn't participating in the promotion, was subject to such ridiculous lines and angry people that the cops had to come.
Exhibit B: KFC itself, last May. Actually, this one's on Oprah. The talk show host offered coupons for two pieces of chicken, two sides, and a biscuit on her website, but many people soon found out their neighborhood KFC's weren't in on the deal.
So, this time around, KFC's offering a piece of grilled chicken through today. Well, maybe. KFC's website says "[f]ree piece selection at manager's choice and may vary by location." This is thinly veiled code for: at your own risk, people. Whatever, KFC.