The panels are plastic, so while this is a concern, they probably wouldn't get much for them. Bumper I'm less sure about.
Though let's be real, Discworld makes just a hair more sense then the flat earther extended universe.
Oh 10°C sounds so nice right now. Short answer is drive more cautiously, you can get undercoated for the salt issue and black ice is just hope and pray.
I stick them in a cork board.