I would like a pragmatic implementation of AgeVer as Arch Linux always adopts: add an AgeCategory value next to username/passwd, saved in etc/shadow, that can b

I would like a pragmatic implementation of AgeVer as Arch Linux always adopts: add an AgeCategory value next to username/passwd, saved in etc/shadow, that can be changed any time with sudo. Then I would give the box to my kids without fear. The problem how it can be implemented in a non-rooted mobile device.