Many primary school students (particularly in upper primary) are active internet users and have personal family accounts with YouTube Kids, Netflix, their own bank accounts (such as through a Dollarmites or Spriggy account) and online gaming accounts.  Pop ups asking for log in details could target young children and trick them into providing sensitive information.

For example, a pop up may say:
“Limited time previews of new Bluey episodes! Log into Netflix now! http://www.nferlhfq;kluireoghiea.netflicks.com”