Just because a radio station owns a trademark on a four letter sequence does not mean that they own all possible uses of that sequence. That is nonsense and we domain holders are getting stampeded by predatory lawyers into throwing away valuable domains.
If you were to set up a website on that domain pretending to be that radio station, or trying to lure that radio station's listeners to their competition that is trademark infringement.
If you were to set up a website on that domain selling shoes, cauliflower, race cars or just about anything else that was not a radio station you are not infringing on their trademark.
Offering it to the radio station for more than your cost is considered bad faith. Parking when ads for that radio station or competing radio stations are displayed by the parking company is a gray area and is better avoided.
Understand that it costs several thousand dollars to prepare and file a UDRP challenge - only the most bull-headed companies would do that for a domain worth a fraction of that amount unless you are deliberately hurting their business.
Someday the Snowe bill, or something like it, could create a feeding frenzy for corporate sharks. That would plunge the internet into chaos, with no website secure. I believe Congress will not be that foolish.