Earlier quoted context omitted.
In this case, I believe Canadians are taking issue with the treatment they may get at the border. They don't want to be sent to detention because of a simple misunderstanding with an over zealous border security guard who is scared of losing their job if they accidentally let the left one in.
My wife was threatened with not being allowed into the country due to a DUI (in the US) from five years ago. We had to pay a $250 fee to spend three days in Victoria.
OTOH Victoria schoolchildren used to do cross border field trips. They ended the practice during the Trump Muslim ban to avoid trauma to kids.