a pin hole in a rubber brake hose would cause the slow and likely unnoticeable loss of brake fluid. at some point. the system would fail.
Note: there are two brake circuits, so a pin hole in one screws up one. Normally design requires a single circuit to meet brake requirements.
In large commercial trucks and trains, brakes are on, unless air pressure turns them off. a pin hole would prevent the vehicle from moving, thus the system is ‘fail-safe’ in addition to having two circuits. I kind of like the truck approach better, but there is a slight delay for the ‘reduced air’ signal to propagate to the brake. When driving, commercial drivers have to antici....pate.
The problem is, you don't know who's going to be "in his way" when that happens.