I think older Guinness drinkers will just see all the trouble as yoofs getting out of hand after drinking too much and won't associate any trouble with Guinness, and indeed this is helped by imagery of gougers holding cans of Dutch Gold.
While Diageo is no doubt laughing all the way to the bank, and it's not putting off older drinkers, I would wonder what it's doing for out international perception as a nation. This level of mass civil disobedience is usually reserved for when someone publishes a cartoon of a prophet, although here it only lasts a day. But is it a day to stay away?