As the others said, the key is mostly in that old saying of never break two laws at once. That law is pretty much obsolete and became all but unenforceable with the evolution of cell phone based scanner apps. Or even cell phones able to connect in a more technical manner, but essentially the plug and play public proliferation of phone apps mean a majority of the population is breaking that law every day.
Of course owning a purpose built scanner, and then external antennas draw additional attention but if you have no reason for LE to have contact with you, and you aren't challenging to them if you are stopped for something simple like a moving violation, you'll probably never have an issue.
Also as frustrating as it can be, the side of the road is not the place to litigate your case even when you know you're right. You run that odd chance of running across an officer that wants cite you for the crime, even when you know you are right. As with any other citation, the place to correct that is with the courts. Have your ducks in a row, but be prepared for that odd jerk that wants to shoot in your lane.
My drive into getting licensed was actually similar to yours. Had a CB in the car in high school and did my fair share of questionably stupid stuff, and wanted a way to legally listen to what was going on while we were out and about. Was really kicked into gear after being questioned by one of the types of officers questioning my illegal in it's own way modified and totally unlicensed President Lincoln II 10/12M CB. Officer knew enough to question why the display showed frequencies, but had absolutely no clue that it couldn't pick up police, and was convinced it was a scanner. Talked my way through that, and figured out how to get my amateur radio license shortly after that.
