I see your point, but listen. Let's say there is this guitar solo in A minor. It lasts about 30 seconds. Halfway through the guitarist - who is quite new to the guitar, by the way, and knows no theory - plays several notes outside the scale, unconsciously (he doesn't know how they sound against the backing chords), then he plays the last part pretty much spot on, except for another few notes outside the scale he hit, that he didn't plan to.

Come on, THIS is an example of a man playing wrong notes. Just say "yes"! I see that from a professional musicians point of view, there might not be a 'wrong' note, but for a new beginner, there sure is. He accidentally played something he didn't plan to, and he didn't know how it would resolve to the rest, thus I'd say he played several wrong notes.

I just want you to say "Yes, in that situation, I'd say 'wrong notes' were played".