I just did flagpoling last Friday at Douglas Peach Arch, BC.
At the boarder to the US, they only gave us an orange sheet of paper, in which the officer wrote down "flagpole", then went inside showing the sheet and they did something but there was no stamp on our passport. No record whatsoever on the passport.
Then you go to Canadian boarder to land. They stamped the date of entry on my passport and signed the CoPR and the officer even gave me a little Canadian flag
!
30 min drive (traffic was very light at 6pm rainy Friday), 30 min wait in the car to the US side, 30 min processing time at both sides (Landing process alone was less than 5 min!)
We did it Friday night so I had to go to Service Canada to renew my SIN this morning (Monday). But I could have it all done (receiving CoPR, landing, getting SIN) in a day (I live in metro Vancouver so the boarder is not far).