maybe your passenger didn't throw a cigerette packet, it was just some other rubbish? Dunno just throwing ideas.
Anyways i've done it - when i see knobs throw cigarette butts onto the road at the lights (clearly see them do it) i get their rego, description, car , road, time etc... and report them. If they want to smoke, thats fine, but don't go throwing shit onto the road - their car has a ashtray! use it or don't smoke in your car!!! really shits me.
But i thought you needed 2 complaints against you before they did anything to stop false claims?