It's interesting, the divide between people who think it's within an establishments rights to ban a customer from consuming food and drink not bought on site and those that think they can mind their own business are from different continents. I have to agree with Diguru and Guden, i dislike the idea of having to buy food (overpriced food at that - how much for a bag of skittles?!) at the cinema, and i really dislike the idea of that spreading into other industries. I also happen to live in Europe like Diguru and Guden.
Maybe it's been happening so long over in the US, people see it as acceptable. It's the same for commercials on TV, by all accounts, you guys get a LOT more than we do, and i already think we get plenty.
If you buy a ticket to wimbledon, you are buying a ticket, it may well be written somewhere 'thou shalt not eat something we didn't sell you on site' but that doesn't make it right. They are effectively taking your right to shop where you like away from you.
I wonder, if you made some sandwiches to take to wimbledon for lunch, which are effectively brandless, would the rules still apply?