Update on our flag-pole experience
Yesterday, my parents successfully landed at the Douglas Crossing here in BC. We drove to arrive to the US border shortly after lunch -- usually humans are slightly happier after they eat. There was no lineup - I obviously consulted travel.gc.ca for border wait times before we left home.
I told the CBP officer at the booth that I was accompanying my parents to do a flag-pole for Canadian immigration. He nodded, gave us the orange slip with a lane number and the comment 'Use flagpole' written on it to present to the CBP officer in the main office, and, to my question whether this administrative refusal would have an impact on my nexus as well as on my parents' future US visit endeavors, he replied 'Not at all'. There was no significant lineup in the main office -- we were out in about 15 minutes.
On the Canadian side, we had the most pleasant experience ever. The booth officer, within a matter of one minute, handed us the yellow slip with the lineup zone and we went in after being directed where to park. There was no lineup at all in the zone allocated to us and we immediately saw a CBSA officer. They were very friendly and very welcoming. After initialing and signing the COPRs, they welcomed my parents to Canada telling them the PR cards would take up to eight weeks to be mailed, and wished us godspeed, as it were.
(Make sure you do the flagpole when it's pouring and windy -- everybody likes working inside...)
All the best everyone!