i think u can help me thx bye

You simply use one or two devices to generate large amounts of IR light to blind any onlookers.
Ok, so not exactly stealthy, but it would make surveillance close to impossible if everyone was using such devices.

Other fun (and slightly crazy) ideas include:
IR screen: tent-like structure around several seats that blocks IR light;
laser that locks on sources of infrared light to cook the source;
fake cameras: certified non-working to stage a conter-suit for violation of privacy;
camera-glasses: looks harmless, the cord around your neck goes to a HD in your belt…

Seriously though, theaters just have to step down from the whole interdiction routine.
I mean, taking away picture-capable phones?
What’s next, flashing you ala-Men In Black so you won’t reveal the ending to others or even remember seeing the film?

In the old days, when small families, single parent households and working mothers were still rare, just about the only place where a young couple could go to get some ‘privacy’ was in the back of the movie theater. No longer. They might now even find themselves in a video – perhaps shot by cinema security – posted on one of those voyeur websites.

What movie-goers really need these days is something to protect their privacy. A device that alerts users when they are being scanned would be a very useful feature, and a camcorder would be the perfect vehicle to introduce this device.