@Cliff ********
Yup. I was "on a list" for SEVERAL years on Air Canada. I arrived legally, but the agent tried to prove I needed a visa and couldn't enter. I knew I was right, I let him know I knew I was right and he was wrong (That was my downfall). After a few hours, he HAD to begrudgingly let me in.
But EVERY flight into the country after that for several years, I was "sent to the other room". I even put the hour wasted in there into my travel/transfer timings over the years. After about 2 years, Canada immigration officers would ask me why I was on the list. I kept saying I have no idea. What does YOUR FILE on me say? They would say there is no details. I would ask "can you remove me?" They would always say no.
Then one day I met my saviour. The female Immigration officer says "I can't tell why you are on the list" I said "I have no idea either". She hits a few keys "ok, there. You are off the list". I thanked her, and told her I had been trying to get off the list for years. She said she was a high ranking supervisor, and could do it.