If he's town-sided, ideally he won't give away ice cream unless he's got a good guess who is going to try and mislead town. Either maf-sided, as suggested earlier, or force him to give ice cream, to make him stay on his toes trying not to screw over town.
I like it. The person will be aware that they are unable to vote, yes? I can see it now- much like people are yakked or people are janned, victims of the ice cream man will be "iced" or they will be "creamed" XD