It's nothing to do with being lucky or not. It's part of the contract you sign up to. I applied for a job in a pub once - the interview was in November and it was made clear at the interview that all hours were paid at flat rate - and one of the questions I was asked at the interview was whether I would be available to work on Christmas Day, Boxing Day, NYE and NYD. It was one of those questions that you felt if you had answered no you may as well not be applying.....
However, with Tesco or any other companies, if enhancements are removed whilst you're in post and you have a contract, it's effectively a breach of contract - so Tesco and others offer "compensation" -
Anyway - we've all talked about it enough already - let's all look forward to our huge compo packages and plan our summer holidays in Hawaii!!