Also, the linear regulator style, they mount using the tab of the 7806 regulator, and the wiring and plugging and unplugging can rip and tear the traces of the single sided PCB causing a number of issues. I've seen plenty of failures, and again, it's mechanical failure then causing electrical failure.
I have not seen a switchmode version of the regulator fail yet, but not all cars use them and so just have not had one cross the repair bench.