Air Canada refused to let me board my flight to Thailand unless I could show a flight out before my visa (90 day tourist visa, the old system a few years ago) expired. I was taking onward flights to Cambodia, but I wanted to book it in Thailand. I had to quickly book a flight I could cancel later to get on the plane. Air Canada said it was a Thai govt requirement.
I was not happy, but I understand where this poster is coming from.