If that's true, it would explain the 61MP number, as Canon could simply upscale the 24MP crop sensor, saving costs.
I really think it's time that manufacturers settled on sensible figures, rather than trying to beat each other in the numbers game. The point will presumably soon be reached where sensors have such high pixel density and small receptors, that diffraction becomes a major problem anyway. I'd much rather that manufacturers concentrated on improving dynamic range and boosting high ISO performance - and most photographers I speak to feel the same way.