Exactly, I did not seen such a screen, but this giants have the budget to hire UX experts to clearly design the initial setup to clearly ask if this device is for a child or if is for multiple users to make more accounts. Also to make happy the other guy that commented they could ask you if you do not want to sure adult content too and in that case set same flags int he system.

Seems such a simple solution rather then each appa nd website having to figure out a way to do it.