When I went through it years ago, it was mostly about making sure you had all your paperwork in order - had the company sponsoring you provided the relevant information regarding the role and why you were needed, did your resume and experience match at all with the work being performed, etc. Basically I showed up with a list of documents and a very nice border guard looked it over and said welcome to Canada. Each time I traveled up there for work, the border guards were polite and professional. Each time I traveled home, I got pulled aside for advanced screening like I was a drug mule. Just loved all the America trivia questions and deep dives into the history of where I live, just so they could feel good about their jobs.

> Each time I traveled up there for work, the border guards were polite and professional. Each time I traveled home, I got pulled aside […]

Interesting, it was the opposite for me, US citizen with CA work permit circa 2016. CBP seemed to not care while CBSA was often irrationally aggressive and suspicious. The closest thing I got to an explanation once after being freed was “We just like you” with a grin.

My experiences with CBSA were pretty bad too.

I was grilled in Vancouver about whether the purpose of my visit was work or pleasure, after I helpfully told the officer that my dad was attending a work conference and I was traveling with him but sightseeing.

"Well which one is it, work or pleasure?!"

I don't know, dude. I just explained the situation: you're supposed to be the expert!

What confuses me even more about that situation is that Canada seems to distinguish between business travel and work travel instead, where those two options seem to be mutually exclusive to each other (199b), and neither is for pleasure

https://laws-lois.justice.gc.ca/eng/regulations/sor-2002-227...

I believe making you flustered is a deliberate part of the procedure. If you don't act 'normal flustered' or panic, it is a signal for more advanced screening.

canada just revised the rules to allow border agents to revoke your visa / work permit, fyi. so look out. it might be better to go during "normal" hours and at major ports of entry to try to get a more senior officer.

Imagine taking a >$500 flight to Japan or South Korea only to be told by the border guard there that you can't enter, even when no rules were broken. And then the flight home is even more expensive. It happens sometimes.