You'd have to look long and wide to find a judge who would consider convicting you for having a malware author borrow code that is clearly not intended as malware.

You would not have to look far for an appeals court who would overturn such a stupid judgement.

To use the example that you brought up, the LAME folks have no worries about being sued for facilitating malware even though their software got used by Sony. (Of course there is the aditional issue of copyright violation there...)