Perhaps the term 'messing around' is too broad for what I mean. Trolling is BROADLY covered by it, yes, but I'd say it counts more as a sort of passive-aggressive form of bullying - you taunt people to get a rise out of them, secure in the knowledge that they have no idea who YOU are, and you may not even be there at that point. The stuff the Beatles did is different because they did it in PERSON - the people they messed with saw who did it, which left them open for retaliation in kind. If you're going to mess with people, that at least is a more honest way of doing it.