Holeinace, you have an interesting perspective on the situation. I can't recall ever being questioned by a police officer about the radios, receivers and transceivers, in my vehicle. I don't pretend to know what goes through the mind of every police officer, but I'd like to think that they never observed me using my radios in the commission of a crime. There was one time when I was stopped for speeding and had a amateur radio transciever sitting on the seat next to me in plain site. The police officer didn't even ask about it.
My take away from all this is that unless I happen to be committing a crime while using a scanner app, I'm probably not going to get in trouble for having such an app on my phone. In the scenario of me sitting in a getaway car listening to a scanner app on my phone while my buddies hold up a liquor store, I'm likely to get busted for having a scanner app on my phone.
However, what is more likely to happen is that the state legislature will address this issue somehow. If they go after the scanner apps, how would they write the law in a manner that can't be easily misconstrued? On the other hand, what if they go after the scanner feeds that are carrying police radio traffic? That would be an interesting situation.