I'm with peederj on this on. This is simply illogical. If the optical low pass filter is, indeed, optical, then it is in hardware. In live view, zoom in as peederj suggests. The resolution is there on the sensor AFTER the optics of the camera. So, any softening would logically come from the downconversion AFTER the sensor and the optics.
Having said that, if you provide an even sharper (dare I say even aliased) image to the same downscaling algorithm, it seems plausible to me that the result might appear sharper. But, that won't necessarily make a better image overall.
I won't be running out to mod my 5D3 any time soon, assuming this is even serious.