I would expect at least a very friendly-flirtatious hand kiss at something like a renaissance festival where people were having fun in character, but not at a convention where you're trying to have a professional relationship with someone, and certainly not to the point where you told them to stop and they didn't. That's absurd, and you're much kinder than I would have been about it. I hope that the issue is resolved, or at the very least, that you don't have to deal with this guy again.