Linn,
I don't know the Texas state statutes, i am from Utah. But I drive a heavy duty tow-truck and in Utah it is perfectly legal to have a scanner. Now I know that I must obide by whatever states "rules" I am in.
I had towed a Tractor-trailer to San Antonio, dropped it and went to Dallas/Ft. Worth and picked up a burned CR England trailer to haul back here to Salt Lake City, UT. I will have to look on the map but I can't remember what weigh station it was even at. I pulled in and stopped on the scale and he come out of the shack and climbed on the step of my rig. He asked for my permits and all that and then proceeded to tell me that is was illegal for a commercial vehicle to have a scanner, even though it was not even on at that point. I didn't know any better so I removed it and he confenscated it and sent me on my way. I can see what you are talking about "chasing" but i didn't even have it on for hell's sakes. That just kinda left a sour taste in my mouth about the state of Texas.