With the ESCs that folk were having problems with, when you change from forward to reverse, you couldn't just pull the stick from one end to the other. You'd have to centre the stick before attempting to reverse, aka full forward -> stop -> backwards. Not ideal for driving.

The other form of braking, which is the type I'm assuming Rory is talking about, is the one where, when you let go of the stick, the motors/wheels come to an abrupt stop, rather than coasting to a standstill. This type of braking is desirable in robot combat as it allows for more precise driving.