I have had scanners since they first came out. The first one I got was because I was a volunteer fireman and wanted to keep track of the town's radio frequencies - this was before we got pagers and our "Plectron" alerts, although supposedly mobile capable were about the size of a modern VCR.
I still have several scanner, a couple of trunk trackers and a couple of analog, and one is on for my local town frequencies until my wife turns the TV up loud to drown it out.
I had one confiscated from me in NY State a while back. One of those times when quoting the relevant chapter and verse of the law to the officer did absolutely no good, he was bound and determined that ALL scanners in vehicles were illegal.
NY State had allowances in the law for hams, people with permits, and "professionals" among others. I was doing a noise survey, looking for the source of noise problems that were getting into the telephones. One of the people living along the road, where I was driving along the shoulder at less than five miles per hour and making frequent stops, called the sheriff's highway patrol and the worthy officer stopped me to ascertain what I was doing.
I happened to be driving an unmarked company car, so visual identification was not immediate. I identified myself, showed ID, and license and registration, explained all of the test equipment and its purposes, and what I was doing there. Then he spotted the scanner sitting on the seat.
He confiscated the scanner, wrote me a ticket, despite my showing him the permission slip to carry a scanner, my ham radio license, and the fact that I was a telephone company engineer doing my job.
I showed up in court at my appointed time and the officer never showed up. The judge said I could have the charge thrown out because the witness wasn't there, but I went ahead anyway, and then he threw the charge out because it was wrong.
Took me a while to get the scanner back, but I did. I suspect it went home with the officer.
When I moved back to Texas I called the DPS and asked about any law governing the carrying of scanners and was told there was none. I asked for it in writing and the young lady I was talking to faxed me a note saying there was no law about carrying scanners in vehicles.