Talking of reminder signs. Car has auto (no brain needed) handbrake. Van obviously not. After three scary moments exiting the van that then began to roll, I now have a red HANDBRAKE sign clearly visible as I leave. (Just near my right knee and the ignition key ...)
One benefit of the often cussed door-side handbrake, and I know from experience, that at least you can yank it on after you've stepped out if the van starts to move.