Let's be honest if that were not on a rugby field the player would be done for assault for kicking the person on the floor like that, even if he hadn't instigated it. While I don't defend or condone what the 'fan' did in any way, the player should have restrained himself. Perhaps he should have just grappled him till security came along and dealt with him?
Ouch, I haven't heard a scream over the mic like that since Cipriani did his ankle in. Such a shame, a player I really admire all round. Wish him a speedy recovery and although it's unlikely, hopefully not miss out on the world cup.