It's pretty obvious what he was trying to accomplish with this lame-brained scheme, as described by OP--and it makes sense only if you assume the signature would stay in place long enough to fool at least one newbie who didn't know any better.  The question I have is how the hell he thought that shit would go undetected for however long it'd be to scam someone.

OK, so maybe his motivations are psychological, i.e., he's psychotic.  In any case, good riddance to a nuisance.  Frontier justice prevails!