The peugeot brothers were investigating braking systems, using bicycles, by throiwing a broom handle into either the front, or the back wheel. They determined that rear wheel braking (on a bicycle) was optimal...on a bicycle.
In cars, having had a number of rear wheel lock-ups, and a few more front wheel lock-ups, I'll take a front wheel lock up anyday.
[mythbusters moment]take a matchbox car, and a 3/4 length of duct tape.
Tape over the front wheels, simulating a front wheels locked condition. Push acrsoss a smooth floor, like tiles or timber...observe.
Tape over the rear wheels, simulating a rear wheels locked condition. Push across a smooth floor...observe[/mythbusters moment]
At least with front wheels locked I don't have to look over my shoulder to see what I'm backing into.