It isn't the majority who are the problem, it's the minority. I go to the cinema once a week and I never encounter the problems people here are claiming to be commonplace. Since my local Cineworld is vile I can't see any benefit in an unlimited card so I either go to the nearest Vue or to whichever independent is showing a good film.
Independents tend to be more expensive and have only one or two screens so the ratio of staff to customers is much higher. You can buy popcorn if you must but there are usually more appropriate snacks like cookies, and instead of huge containers of fizzy drinks you can buy tea, coffee, premium beers or wine to take in. By promoting the cinema as a pleasant, relaxing place to see a film these cinemas make antisocial behaviour far less acceptable. Presumably this is why Odeon are experimenting with premium facilities, but since Odeons are soulless, unfriendly places it's unlikely to make potential miscreants think twice about misbehaving.
Vues are somewhere in between since they are designed to make the filmgoing experience more enjoyable - tiered seating, good sound - but they are understaffed and determined to sell sugar-filled drinks and confectionery until everyone in the audience is in a hyperglycemic coma. As others have pointed out they need to be much stricter in ensuring that kiRAB only get into the film they've paid to see.
But compare independent cinemas to multiplexes of any breed and you can immediately see the root of the problem: multiplexes are designed with large communal areas where people mill around without any real purpose. They're like overlit clubs, with everyone hanging around in little groups and a feeling of tension because no one is really relaxed. Independents, on the other hand, don't have the space to allow this and whilst they can feel crowded before and after the screening they fill and empty quickly. Surely the cause of much of the bad behaviour people report here is bad cinema design?
The fact that so many posters believe there's a problem can't be ignored but it does seem to affect some cinemas and some areas much more than others. I can't imagine a time when I wouldn't go to the cinema; it's part of the weekend and it's still better value than an evening in the pub. As long as you don't buy popcorn, of course.