61 and 91 flying should be exempt from far 117 limits as I understand it. We are actually moving to get SKW to rescind their policy prohibiting outside flying, since it no longer affects legality per FAR 117.

Outside flying could still be a fatigue issue, but so could any other moonlight job, running a marathon, staying up with a cranky baby, closing the bars down...ie life in general. It's up to the pilot to manage that responsibly.

The hangup might actually be ICAO...apparently airlines doing international ops under ICAO have some sort of record-keeping requirement related to flight times. Outside flying may still fall under this, and there's no easy way to track it.