Doug, Tesla's do not have emergency brakes but they are not unusual in this regard. Most cars are now using EPB's and no longer have emergency brakes. I'm sure the manufacturers (and perhaps even D.O.T.) would argue that emergency brakes and manually actuated parking brakes cause more accidents than they prevent. A manual parking brake requires some expertise to be used as an emergency brake. If the operator applies too much rear brake, a loss of directional control is the likely result. Also, the chances of a simultaneous failure of the front and rear brake hydraulic circuits is probably nil.
I'm sure most jurisdictions have regulations that make removing or modifying any safety device illegal; however, many modifications we make to our Panteras violate such regulations. Aftermarket seat belts, steering wheels, fiberglass bumpers, brake master cylinders, proportioning valves or even Wilwood brake kits likely violate these regulations, as would the removal of the OEM pressure reducing valve in the front brake circuit.