Radio staying on?
You don't mention what you are driving, but most newer vehicles have a feature that will allow the radio to continue to play after the vehicle has been shut off, even with the key removed from the ignition. It will continue to play for a few minutes until it times out and shuts itself off. Or, it should shut off after you open the drivers door. Both these ways will shut the radio off to keep the battery from dying. Check owners manual for more information. Try it and update thread.