One roll away vehicle changed my mind on E-brakes, and like I said that vehicle had an autotrans. Turns out a linkage bushing was worn out so it wasn't fully engaging in park. However after I wrote my initial comment I remember having a class c motorhome without a working E-brake and I did the block of wood thing, but it was just a pain in the ass to me, but that's me, we are all different.
Somewhat related funny story... I was an M1 mechanic and recovery guy in 1st Cav at Ft. Hood in the early 2000's. We were out in the field in between deployments and we had a tank catch on fire. The crew popped the fire bottles and shut it down, no big deal. Turns out there was a manufacturing defect in a fuel system component and ALL M1's worldwide were marked non-op until they could be inspected. Well, we were in the field so all our tanks had to stop where they were and shut down until we could go pick them up and bring them in for inspection of the bad part. Rather than try to tow in 14 tanks, one at a time, from all over Ft. Hood, with our recovery vehicle we decided to send out the transportation guys with low-boy trailers to haul them in.
The first one came in and it couldn't be started to unload from the low boy. So we got our recovery vehicle behind it and pulled it off the trailer. To stop it after it unloaded, we had a tanker in the drivers seat and he was just going to hit the parking brake when it had rolled all the way off the trailer. This was sketchy to everyone, but we couldn't think of a better way, so we got the recovery vehicle about 150 ft away and used the main winch to do the pulling.
Well.. we start pulling and the tank rolls off the trailer, at the top of a hill. Everyone yells for the guy to hit the brakes and his eyes get big and it just starts picking up speed down the hill. Everyone starts running after it screaming for him to hit the brakes... it just barrels down the hill and right into a bunch of mesquite and trees. The poor PFC's platoon sergeant and everyone else in his chain of command just starts laying into this kid while we try to figure out what the heck happened. He keeps repeating that he DID hit the brakes and it just kept going.
Turns out they had pulled the final drives to load it onto the trailer and then replaced the caps so we couldn't see they had been pulled. The parking brakes for an M1 are INSIDE the transmission, so with the final drives pulled, there is no brakes... period. Thankfully no-one was behind it.. there is nothing like 71 tons of freedom barreling down a hill backwards to make you appreciate brakes.