Having read through part of the Crossair report, it seems that the Captain was instructing IFR immediately before his commercial flying.
This is totally at odds with what I'm wishing to defend. Instructing immediately before flying opens up all types of FTL issues and in mind is an absolute no no.
Flying a couple of light aircraft trips per day off followed by at least minimum rest before any commercial activity is what I am wishing to keep in place. This I believe will be far less fatiguing than many non flying activities people pursue on their days off.
I do not agree with supposition that flying light aircraft on a day off increases an employers risk, in fact I believe the case to be the polar opposite. Constantly, hand flying, stall recovering, flying go-arounds and UAs can only help increase safety when monitoring the autopilot.