I am not so sure the airline has a real leg to stand on for a couple reasons, what if you brought a ticket to go LHR-YVR for say 2 weeks...then during your stay urgent business came up and you had to go back to the uk for say 3 days..

Well thats nesting.....

Plus would a judgement fall to the airlines who are know to offer the most unfair contracts in the world...

I would be careful cause as we all know, AC would spend a dollar to save a cent.