I think the selling of 3D glasses, especially kids one would be a good idea. I keep wanting to get my daughter a pair that would fit her, but would have no clue which ones would interact with the rides properly.
The only issue I see with this, is the tech for the newer rides (spiderman, superman, etc) is different than the tech for the older rides (Shrek, T2). So not sure if the higher tech glasses would work for the lower tech ones. Hence why I have never done the research to figure out if I can get glasses for her. The big ones given out at the parks fall off of her and she now likes to keep them on the whole time when watching 3D shows like Shrek or Philharmonic.