What I do think is rather cheeky is Odeon's 'Own your 3D glasses' thing. Now, you pay a pound for something you used to borrow for free, which is absolutely no use outside the cinema, and if you forget to bring them to your next 3D film, it's your fault and you have to buy another pair.
I mean, it makes perfect sense from a business perspective, but touting it like it's good for the customer is just lying.