Bottom line it is difficult to prove.
besides the officer would have to have been keeping pace looking in my window and I would have to be a complete idiot, not to notice him.
Not as difficult as one would think.
First, you have to keep in mind that these citations carry fines that are typically less than $50. Few people are going to take such a citation to trial, so there is normally not going to be a need to prove anything. Most people will plea guilty, and the municipality will get what it wants: increased revenue.
Second, most municipal prosecutors aren't willing to dismiss these types of charges, unless you've also been charged with something more serious (such as a DUI, reckless driving, etc.). Then they are more willing to drop the lesser charges if you are willing to plea to the more serious charges.
Third, even if you were to challenge your municipal ordinance violation by taking it to trial, you don't get a jury trial in municipal courts in Alabama; you'd have a bench trial in which the judge is the fact finder. Most municipal judges would be inclined to side with the testimony of the officer, so your attempt at showing that it can't be proven by taking it to trial would be in vain. This is, afterall, how many people get convicted of a DUI at the municipal level when no breathalyzer test was administered.