I suppose that might be nice, but it serves no purpose to them and the bottom line it is not really what they are paid to, so yes they would want payment and I suspect there would still be data protection issue.
I might add that I found the person who built my car and he would not respond to any of my enquiries/messages. He probably thought that I had found something wrong with it and didn't want leave himself open to criticism or a load of questions - there isn't anything wrong as far as I know, but I would like to know what the silver button on the dash is supposed to do!