If the resistance is high enough to restrict the current draw down to about 2 amps, then the module would only draw 2 amps even if it's regulated for 2.8A.
But if the resistance is near zero(say, with a solid piece of copper instead of a spring) and the light would draw 10A in direct drive, then regulation would force the current to drop to 2.8A.
That's what I'm thinking anyways. It would be interesting to put regulation on the Moddoo Triple so that it runs with 4.5A and then lower the resistance down to nothing. At the very least that ought to minimize sag from the battery while making sure it doesn't draw enough current to damage the emitters or the battery.