And, to be honest, he should be cautious singing cheap guitars, because no one in his right mind is going to give Mark Knopfler a $100 guitar to sign. You have to have negative IQ score to do that. I understand taking his Signature Martin Ragpicker to... scribe another signature on it, but you kind of need to feel whether you sign things for a genuine fan or for an idiot. Luckily, I've never had a privilege of asking Mark to sign something.