^ ^ Just take the button out of the hand brake, pull the spring out, use a door lock button from an old ford or holden etc (the type that uses a "T" shaped button) or mod up something so that when the handbrake is pulled up the button can be pulled out to hold the brake on (aka - spin turn knob/button)
But just like what Taz said - its something that can quite easily be overlooked by either the owner or borrower of the car.
And yes KE55PIG, i know you've said "Not for a road car" but its also for the one thinking of it for their road car....
Yeah thats right, you. You there scratching your chin thinking "Hmmm, interesting"
Another one is if one of the lines blows out or fluid is lost from the brakes, at least you have a cable handbrake for redundancy