When I left my car for an oil change, my radio

[Muriel]

98. This is not okay and illustrates the de-evolution of social our social constructs

Without knowing what make/model your car is, it's impossible to determine whether the tech had a need to turn the ignition on to reset the "change oil" dash message. If that was the case, anything beyond turning the volume down is just plain unprofessional. Those posting that we should just get over it or give the guy a pass, don't understand that by allowing this we slide further and further away from what we as paying customers expect and instead find ourselves dealing with under paid, poorly trained workers who aren't invested in their jobs.
I'm willing to bet that changing that station was done on purpose and meant to have the exact affect that it had with the original poster, but tolerating this seemingly insignificant slight only sets the bar lower and lower.