I said not KFC. Anyway, the reason why getting a private booth at these places is recommended is because it's a small gesture of romance that you're showing to the girl. Small gestures net you way more points in her book than large, overly flashy ones. This is important. Capitalizing on this point is the way to win a girl's heart.
Taking her out to Wendy's, opening her ketchup packet for her, and dumping the tray into the garbage when you're finished alone will leave a big impression on your date. It's understandable if you think this sort of thing is contrary to reason, but that's females for you. Just trust me on this.