Ive only had it freeze once when extremely cold.In all my years driving I have never had a car hand brake seize when in use or needed to change cable due to stretch.
Your engine can let the car move as the cylinder pressure leaks away.
The stretched cable issue was more of a problem in the 80's. I've changed several, where you are out of adjustment at the lever end due to cable stretch. It was quite common then, to the point of motor factors selling a device that sat on a straight stretch of cable and you screwed it in to take up the slack. I can't be the only one old enough to remembers these! I think they became illegal for an "MOT work around" at some point though!
Maybe the cable quality has improved.
I had a Landover discovery once, my wife parked it on Redcar high st, went shopping and returned to find it in the middle of the high street! She hadn't pulled the lever hard enough, so she leaves it in gear now too.
I think there's enough compression in my diesel engine to hold the car better than the hand brake!