this in nothing new but not practiced. The -ve to ground of car with bad battery is suppoed to prevent explosion of the bad battery from happening. Most people just clamp the -ve of bad battery. Other thing to take note is to connect the positive first and not the other way round. The last point to connect is the ground point of the car with the bad battery to complete the circuit.
There is another thing which is recommended, after the connection, run the car with the good battery for a few minutes to charged up the drained battery, then off the engine before having the car with the bad battery crank his engine, this is to prevent extra load on the alternator when the engine is on. Extra power pulled from the alternator during cranking could damaged it.
With a good jump start cable with low resistance, good battery is supposed to be able to start the other engine as if it's connected to it's circuit and thus it is not necessary to have the engine of the boosting car to be on.
BTW, not an electrical engineer so I might be wrong.