I have fished before with a slung shotgun. This was up in the Terrace area during the September / October run of northern coho.
When you are fishing the Skeena / Lakelse / Exstew / Copper / Exchamsiks; the Grizzlies are as plentiful as the coho !! We were hiking the river, as we did not have the luxury and safety of a boat. There were many locals who claimed that NOT taking a shotgun was dangerous. After a number of trips up there, I have to agree. I never had an issue with any CO / DFO / RCMP who happened to come by.