Technically it's not a radio artifact. It was a warning label attached to each of the LPs at the Torrance Public Library. The LPs were not played at any radio station, but I like it.
Note the typewriter font, and the hand-drawn sweating sedan. This is not clip-art. This a sincere warning to the misguided that improperly store vinyl.
The inside of a car can be easily 20 degrees hotter than the outside. If it's hot enough to kill children and small dogs it definitely will warp your records. Vinyl should be stored at a temperature no warmer than 70 degrees. A car can get warmer than that on a cloudy day in March.