I guess you have never driven a quick Mini in anger then
I have had it happen many times. Being towed home by my father, me in his just purchased MG with a very poor handbrake and no horn stands out in my memory!
Another good one was in a 280ZX towing a trailer with an Orion on board and the pedal disappeared going into a roundabout.
I am happy to report that no collision ensued.
Many times I have had to change old fluid to get a good pedal, this has to be a safety concern, especially at higher speeds.