I have OC'd my pistol while backpacking for three seasons now... it was my intro to open carry.
I have heard a few teens say "Woah!" or "Did you see that?" as I passed by. I have had some wide eyes and possibly disapproving looks... though it could have been trail weariness.
Only one time did someone actually ask me about it... an old timer at Packwood Lake, July 09, asked if my thigh-mounted Serpa was a police holster... we chatted briefly.
Then last month, 7/21 at the Greenwater Lakes trail head my wife and I were waiting for friends so we could drive up Dalles Ridge and begin our hike down to Lost Lake. I was standing near my rig in the parking lot, looking at my map, when a couple came down off the trail walking their dogs.
The wife obviously saw my pistol and the way I was dressed... she asked, "Are you giving us a ticket?"
I didn't hear the first time, so I asked her to repeat herself and she did... and added, "We forgot our Forest Pass, are you going to give us a ticket? We have one, I promise. We just forgot it."
I laughed, so did my wife.
I replied, "No, I am not law enforcement. And I promise not to tell on you." With my most charming smile...
At that point they took off. Apparently a kind civilian with a gun is more intimidating than a ticket from a LEO.
Usually though, I pass by everybody I see without discussion. Or they wander past me or past my camp site without much more than a hello. Children, teens and adults alike... most of them do not even bother to bring it up.