No, he's not. He lost against Merkel in 2013, which is bad enough. But he clearly is the better thief. Just put it in your pocket, like it's yours all along.
Klaus does it unprofessionally. He looks at the pen and thinks "I'm taking this home with me", but then realizes that people are watching, so he tries hard to hide what he's doing.
Fun fact: Klaus means "Steal it!" in German.