Lets say you find extra wires added at the battery positive or the starter relay junction.
Maybe there's electric fans, or fuel pump, or???
That would be a completely different situation than a factory setup. In the factory setup, current only goes through the ammeter during start, and to recharge the battery. (This is what MAD gets wrong in their explanation. They say all of the car's electricity flows through the ammeter. That's not true.)
You would either want to get rid of that accessory, or use a different approach to powering it.
Or maybe that's not what you find, but you find the green field wire is pinched against against some sheet metal so its grounded.
That would mean the field is constantly powered and so voltage was increasing with rpm. This would cause the battery to overcharge and the operator ignored the ammeter.
These are just two examples of what might be found.
Different situations require different solutions. Further a solution that might work for me, might not work for you. I might ditch the aftermarket mods and go factory. Another person loves the modification - lets say its an EFI system - and rewires to handle that system.
For example on my own car, I've added headlight relays at the alternator, and a parallel wire feed from the alternator to the ammeter. This second feed wire also serves as a junction for the MSD 6T. I did the first because the headlights draw more current than the originals. The second because I wanted the MSD to get power more directly from the alternator, and because the alternator output junction at the bulkhead got somewhat overheated when I was forced to recharge a low battery using the alternator.
