they wanted to ensure the experience was not spoiled for younger children on their first cinema trip

Sounds a bit disingenuous. Seems more likely they are catering to the parents of those younger children than the younger children themselves. Most young children would have more fun (not to mention development gain) from watching older children goofing off than they would watching a movie in silence. Same reason doctors and child psychologists advise parents "TV time" isn't bad, but you should watch with your children and talk about it with them (while watching).

Children need to have a few real experiences before they can start worrying about the best conditions for being absorbed into a virtual one...