It wasn't though. The phone may have said 'Vodaphone' on it, but it was an unlocked phone and actually had an 'o2' sim in it. The cashier doesn't have any right to press the back up button on my phone to check what sim is in it. He didn't even ask to see this, he just flat out refused.
At the end of the day, Orange have got their 25p (or whatever it costs to text the Orange Wednesday service), so i just fail to see the problem with the cinema honouring a valid Orange Wednesday code.