[BrianG]

Depends on how the supply handles overcurrent situations and whether it is a linear or switching supply. Some may simply shut down. Some may blow an internal fuse. Some may exhibit drooping output voltage. In all cases, the ESC (motor actually) will try to pull what it needs to do what is being asked. To have the ESC "stop" once it reaches X current requires the ESC have some kind of built-in current-limiting and then program it.

Whatever you do use, I would add a large (~6-8A) Schottky diode across the regulator circuit. When you apply brakes to a motor, it will generate a reverse-voltage, and if this voltage is higher than what the supply is outputting, the regulator circuits could fry depending on how they're designed. Adding the diode to a switch mode supply may be a bit tricky and is more complex than can be described here. However, if using a linear supply, you would add a reverse-biased diode across the regulator circuit (anode to the PS output, cathode to the rectifier). That way, if the voltage from the ESC does get too high, that extra power will be shunted directly to the rectifier.