Did some testing on this:
SX30 & SX40 - crashed without the patch, work ok with the patch (both have a dedicated video button).
G12 - does not have video button so no change; but the SD override does not work in video mode even in MF.
G1X - has video button, did not crash, SD override did not work unless in MF mode so the patch does not effect functionality.
I'd be inclined to add this as another #define rather than tie it CAM_HAS_VIDEO_BUTTON.
Phil.