I've made my living troubleshooting electronic (radio, radar, siren, microcontrollers) for 34 years and I can tell you that what you posted makes little sense. If what they were doing really made the engine die, they were doing something pitifully wrong.
It IS possible that the alternator has a shorted diode, and that would drain the battery somewhat quickly. But the diodes are not part of the regulator - if this is the issue, get a new alternator and be done with it. Here near Atlanta, I bought my SE a new Valeo alternator for $199, took three hours to wrestle the old one off and put the new one on (with time to run to the store in between).
When the rebuilt one died, I had it replaced in an hour.
Now, if you really want to find out what is draining the battery, there is one way:
- With the car off, doors and trunk lid closed, disconnect the negative battery cable.
- Insert a digital meter set to measure current in series with the battery negative post and the battery cable.
- Current of up to 1/2 amp will flow, wait 90to 120 seconds for all the modules in the car to initialize and then hibernate; the current will do down.
- After two or more minutes, if you see any current over 55mA (or .055 amp), you have a problem.
If you see too much current, remove one of the 50 amp fuses in the little box next to the battery. If the current does not go away, remove the other 50 amp fuse. (One feeds the engine fan module and one feeds the antilock system). If you still have current, remove the 200 amp fuse.
If you STILL have current, it is almost 100% certain the alternator is doing it. If removing the three fuses makes the current go to zero (and it should) then put the 200 amp one in and start pulling fuses in the box on the driver's side of the engine compartment.
I suspect you have a lot of current, on the order of several amps, in order ot kill your battery as fast as it is happening, so this should be easy to find, and not TOO hard to fix, depending on what it is.