Well RMF, I have a 14 year old ''pin in the transmision'' and it seems to be a pretty solid/reliable pin. I have parked on hills over the last 11 years with this car.
I probably also have some very rusty parking brake cables and I would not dare trying them to see if they still work.
Same story with my 1978 Vette (which I have owned for 11 years) and my 1974 MGB .
Parking brake are to be used when ''the pin'' fail.