In apps marketed for children 5 and under in the Google Play store, there were pop-up ads with disturbing imagery. There were ads that no child could reasonably be expected to close out of, and which, when triggered, would send a player into more ads. Dancing treasure chests would give young players points for watching video ads, potentially endlessly.
The vast majority of ads were not marked at all.
Characters in children’s games gently pressured the kids to make purchases, a practice known as host-selling, banned in children’s TV programs in 1974 by the Federal Trade Commission.
At other times an onscreen character would cry if the child did not buy something.