Is this one of those features that's disabled on consumer cards for market segmentation?
An imperfect analogy: a small neighborhood of ~15 houses is under construction. Normally it might have a 200kva transformer sitting at the corner, which provides appropriate power from the grid.
But there is a transformer shortage, so the contractor installs a commercial grade 1250kva transformer. It can power many more houses than required, so it's operating way under capacity.
One day, a resident decides he wants to start a massive grow farm, and figures out how to activate that extra transformer capacity just for his house. That "activation" is what geohot found
Nvidia does this so that customers that need that feature are forced to buy more expensive systems instead of building a solution with the cheaper "consumer-grade" cards targeted at gamers and enthusiasts.
And then everyone on that neighborhood would still lose power, because there's also a set of fuses upstream of the transformer, and they would be sized for the correct current limit even when the transformer is oversized. These fuses also protect the wiring upstream of the transformer, and their sizing and timings is coordinated with fuses or breakers even further upstream so that any fault is cleared by the protective device closest to the fault.
Nobody's taking more than their share of any resources when they enable this feature.
A better example would be one in which the consumer has a dedicated transformer. For instance, a small commercial building which directly receives 3-phase 13.8 kV power; these are very common around here, and these buildings have their own individual transformers to lower the voltage to 3-phase 127V/220V.