I know children are extraordinarily well behaved and have no rebellious or anti-authoritarian tendencies in Japan but the notion that 'omg this game is real and risks death so children can't/won't/mustn't risk playing it' seems like quitea stretch. On the whole children are less likely to be afraid of death than adults because they have more trouble conceptualizing that they could cease to exist as a consequence of a particular behavior. Additionally, children are generally more solipsistic and would be comparatively less inclined to believe that 'it could happen to me' in the face of seeing other players die, plus they could very well just not believe that they will die if they die in the game. I wonder if the starting town has a silk cage to keep all the poor helpless children from facing the big scary fake world whether they want to or not despite the fact that the kids are ultimately in no more danger from the world than any of the adults 'guarding' them given the setting.