Citroen had the same problem on the Xantia which had the handbrake on the front discs. There recall mod was to grind the first three indents from the hanbrake quadrent so you had to pull it up a long way before the pawl would engage.

i had this exact same problem on my focus RS, parked up got my stuff out, turn the engine off locked up and as i walked away i started to hear the car slide down the hill and straight into a concrete post..........