Facebook had a literal best practice internally referred to as "friendly fraud", when children bought in game items without their parents' knowledge. Facebook encouraged the practice of deceptive UIs and refused refunds to parents.

This entire culture was a huge part of why I stopped working on Facebook games in 2010 (before that market crashed). My stomach hurt when I thought of the dozens of people paying $1000s/month on the fake zoo animals in our games.

https://www.revealnews.org/article/facebook-knowingly-duped-game-playing-kids-and-their-parents-out-of-money/