I have, but I'm not American. When I'm in the US though I'll only go to fastfood places we don't have at home so Jack In The Box, Taco Bell, Wendys, Whataburger & of course Sonic (I'm sure I'll have to change that rule next year when I move there).

And Yep Free Wi-Fi for McDonalds in Australia and it's OK, not lightning fast does take some time to log on and has a download limit but it's great for the price!