That isn't the subject of the thread at all - that's just the topic you've dwelled on.
Most people have talked about whether blocking cell phone usage by any method, legal or illegal, is a good idea for movie theaters.
The article describes efforts by theater owners to legalize the use of cell phone jammers. It's already acknowledged that that's illegal today, and it should further be taken as a given that business practices that get you arrested are a bad idea. The only meaningful question is: should the theater owners' request be granted?
For most of us, the answer is yes, on the basis of private property rights. That passive shielding is legal is pointed out to illustrate the stupidity of outlawing active methods that produce the same results at lower cost.
For the rest of us, the answer is no, on the grounds that we want our cellphones/pagers/blueberries, and we'll stamp our little feet if we can't have them. This group generally refuses to acknowledge that they must do business elsewhere when they find the terms disagreeable in one establishment.
Meanwhile as a side-show, RFEngineer offers asinine assertions such as the claim that jamming is impossible without also jamming cellphones on others' private property--or, when he realizes he can't prove that, he offers the stunningly obvious observation that it's illegal today. Naturally, since if it were legal, theater owners wouldn't be trying to get it legalized.
Are you fully up to speed now?