I've heard one or two pundits and ex players suggesting that a points deduction would be the best deterrent. Bad idea. What's to stop a rival fan from another club pretending to be from the home side and commiting the same act?
I did initially think that myself but on reflection i think it's highly unlikely that the kind of gobshite that would do something like this would be able to pass themselves off as a fan of another club. I think it could be determined quite quickly via their match attendance history and social media etc who they really support and what their motivation is.