I was listening to some action on 142.770 around the supper hour yesterday. Didn't even have to listen to Fleetnet !
Turns out it was a joint effort with TPS and OPP to do a grid search for a missing 12 year old girl (who has subsequently been re-united with her family.)
I also monitored this search. I got the impression that CF-OPP was transmitting on 142.7700 to ground units instead of going through the repeater. Makes sense as they would obviously have good coverage of any scene altitude wise.