When I go to kids parties I never eat the cake. One time(at band camp), one of the parents kept trying to get me to take a piece and I kept politely declining but she was insistent. I finally had to tell her why I don't eat cake at a kids party and she got offended telling me her kids weren't sick or anything. I told her I don't care if she is or isn't sick, I'd rather save the saliva swap for my GF. That didn't go over very well with her and she proceeded to tell the rest of the parents my Kid/Cake stance. Some got offended and some agreed with me. The whole thing turned into a heavy discussion veering off into all kinds of idiotic tangents.
While all this was going on I quietly scooped up my son and exited the party just as the tensions were starting to peak. Don't remember ever getting invited to another party at that house........