My commuter bike only has a front brake. You can shift body position to make it pretty much impossible to go OTB. Meanwhile my DJ bike only has a rear brake, which at best "strongly suggests" you slow down.
Also it might be a decent config for learning some BMX tricks because if you want to be able to do a barspin you can not have both brakes.
And if you have a bicycle with a coaster hub and a front brake and your chain is off than you are effectively having only front brakes.