I think it would be pretty dumb for any judge to allow the evidence a search yielded based on the appearance of pistachio shells. If he/she did, they'd basically be setting the precedent that it's obviously OK for police to subvert citizens 4th amendment rights based solely on the officers opinion, not observable fact. Just like it would be unconstitutional for a cop to stop and frisk you for being the wrong color. The color of your skin doesn't give you probable cause, just like having pistachio shells in the cup holder, and you pretend like you think it's actually marijuana doesn't.