You can, and do win. I've debated with cops over traffic/defect matters and gotten off. Its how you do it, and how smart you are in getting your point across.
I think this is developing into a sad world: where you try to do the right thing by the cops (engineers certificate/racing or drifting at the race track), yet they will still go out of their way to nick you anyway. There's our reward for doing the right thing. Then on the other side of the coin, you get people who just give up and don't even try to debate the point. When you're busted fair and square speeding or whatever, yeah cop it sweet and pay the fine. But when you know you're being nicked for no reason at all, don't lie down.