My dd age 6 had a playdate at a friends house and I found her hiding a toy in her room afterwards. She lied through her teeth about it: friend gave her it, she found it in our house and doesn't know how it got there, she saw her little brother take it from friends house. Eventually told the truth after each story was challenged and admitted she took it. We're going back to return the toy and I'm sure the mother is going to be lovely about it but I'd like to really teach her a lesson, would it be reasonable to prewarn the mother and ask her not to be so immediately forgiving? We're punishing her with no tablet for a week and no staying up late tonight (she'd normally watch strictly).