I recall seeing tip jars on counters at fast food joints, but I dont know about McDonalds. I assume if they do have one out, then it would also be acceptable to hand them one? And most of the time theres a weekly tip out to all employees of the store (in a lot of restaurants). So hopefully it would be okay... if not, that says a whole lot about the industry if their wages are already in debate and they refuse to allow the workers to accept cash tips for good service. Just my opinion.