regarding flagpoling and landing let me clarify
flagpoling-when you dont have US VISA...you go out of Canada to the US side and come back into Canada to do your landing procedures...the US side gives you a Admin refusal letter in most cases...i havent heard that they stamp the refusal on your passport..... that refusal has no impact on applying to the US in the future...
if you do have a US VISA -you go out of Canada into US and come back for landing
My case- I have a US VISA...i drove out of Canada...100 metres between Canada and US is No mans land..i drove till there..never went to US side and came to Canada border to do landing...
By the way, when you go to land, you have to take all your WP/SP-all previously issued...on landing...all of them become null and void...because your status changes and you become PR
Best wishes!