Jayne, they don't marry their sisters, but they often marry each others' sisters. My friend's sister is engaged to his best man.
Young lads don't know enough about it, I'm sure, or they'd be in there like a shot. Where else do you get to join a men-only club, take swipes at each other with thumping great sticks and chase girls around a pub garden, then retiring into the pub for a pint of rea ale before making your way to the next pub to do it all over again.
It's not all hankies and bells, I can tell you that.