[MEvang]

Good questions, the first one I can answer. Split diagonal braking systems are used manly on front wheel drive cars or can be used on any vehicle that has low rear braking capabilities. Most fwd vehicle have very small rear brakes that only contribute about 20% or less to the braking. On a dual master cylinder system if you split the braking up front and rear and the front brakes are lost, you simply can't stop the car safely on the rear brakes alone. So they in turn split the system diagonally right front, left rear on one side and left front, right rear on the other. This way you always have one front and one rear brake to stop on if hydraulic pressure is lost on one side.
The other question I am not sure of. I take it this is no longer true since they are alowing electrical park brakes systems to be used.
The last on I don't quite understand. Do mean by break out of park, that a vehicle could slip out of the transmissions park gear?
Mike