Do pros ever make mistakes?

For Christmas I was given a DVD - Carlos Santana plays blues at Montreaux, and featuring Clarence 'Gatemouth' Brown, Buddy Guy and Bobby Parker.

It's a curious CD, not least because of CS's Blues solos: it looks and sounds wrong to see him playing in a box that doesn't allow him to really express himself with his usual voice, although he plays well enough. But the odd thing for me has been to see some of his guests.

On one track the aforementioned Mr. Brown was playing in the wrong key (he plays in a box around open strings using a capo) and apparently failed to realise it. It wasn't until the bass player leaned over to him after a couple of verses and has a conversation that he seemed to realise and change to the right key. Weird, especially as his style indicates that he *should* be playing by ear rather than rote.

Then Bobby parker came on and instantly has enormous tuning issues with the E and B strings. Again, even weirder, though not his fault this time. He's clearly thrown by this too, and when he does get in tune, he's clearly playing in CS's shadow.

One of the things that marked out the difference between amateur and professional players for me is that pros just didn't make these kind of mistakes. You'd expect Clapton to know he was in the wrong key instantly and fix it, wouldn't you? Or maybe it's the difference between a kind of music that is slick and carefully produced and one that is allowed to happen according to feelings and the occasion. If that's the case I can identify much more readily with it. I'd rather play spontaneously and have the occasional trainwreck here and there but create according to the circumstances than produce the same show every night.

Wonder if that's what keeps these guys fresh and spontaneous instead of just grinding out the same old blues riffs each time? Or maybe they're just sloppy like me?