As an actor, there are certain things expected of you that maybe aren't expected from your everyday insurance claims adjuster. You have to be on your theatrical game at all times. You can't just be Gerard Butler, for example, you have to be "Gerard Butler" and break out your song and tap dance and "This is Sparta!" talents to entertain the masses every now and then. It's just another part of the gig.
Like when you appear on German television and the host expects you to crack a walnut with your ass and then pour ice down the front of your pants, because it would be funny and it's supposed to be an entertaining television program. That's when you're "Gerard Butler," and indeed, that's when Gerard Butler was "Gerard Butler, Ass Walnut Cracker."
Regardless, it's hard to fault Butler's reasoning. The Germans are...how do we say...their own bunch. They do things a bit differently, like celebrate people who can crack walnuts with their asses. Butler was merely doing as the Berliners do. Ich bin Gerard Butler Berliner, right? No?
All that said, we have to think that the next time he's invited back, Butler will have some sort of "unfortunate and un-reschedulable conflict and he's really sorry," for the sake of his nether-regions.