On a semi-related note, do we really think it was O playing the keys on Ensayo de un Desaparecido? I know he's got skills and all, but the level of proficiency there sounds like a trained musician, and not what I would expect out of O.
Lots of people believe that he played a lot of the keys on the ipecac, I think.
But I'm with you. There's a possibility of course.
I don't know why someone would think he did in the first place. There's not even credits for the series.
Maybe Chris didn't play drums after all and it was Omar...
Maybe most people who believe that probably don't play any instruments themselves.?!?
If Omar played all or most of that he would have had to sit down and analyse "traditional" piano playing to an extent that he did not do for his guitar playing.
Wouldn't be what you expect of him.