I do think though, that if 3D movies are going to get more and more common, you should be able to keep your 3D glasses and use them again and pay less.
Our theater lets us keep the 3D glasses (they don't want them back; no receptacle to drop them in). However, there is no discount for BYOG (Bring Your Own Glasses).
The price difference between a regular movie and a 3D movie is $3.50. Most likely they pay a lot less than this for these glasses, making the glasses a profit center. Could explain why you'll never see a BYOG price.
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Armand