Board Thread:Questions and Answers/@comment-24487529-20150302230813/@comment-6697950-20150303202749

This issue wasn't really addressed anywhere in the novel. Technically, Sasha didn't state the exact years of the children and her assumption of their age was just an assumption (and the anime doesn't necessarily follow the plot accurately), but it's a fact that Silica started playing when she was twelve, meaning that eiher the NerveGear itself isn't capable of judging the player's age accurately (I highly doubt that there are accurate markers in the brain that the NerveGear could look for to determine the player's exact age), in which case one can just falsify their age and no one would be able to prove that the player is underage. Or, there are ways around the restriction (e.g. someone else set up the NerveGear for you, since you only need to calibrate it the first time). I could continue this train of logic, but everything farther than this would probably just be speculation and this topic is not in the speculation board. It was never explained what kind of restriction it is.