Oh dear, I don't know about the children but I can remember doing it myself when I was about 7.
Both sets of my grandparents had died before I was born and I felt a bit left out when other kids were going on about theirs so I decided to invent a grandpa. I told everyone at school he was coming to stay with us for the weekend and how lovely he was, etc., etc. The teacher overheard me and asked me where he lived and how old he was. In my panic I said he lived in Australia and was 110. I think she twigged!
Anyway, it taught me a lesson. No more little white whoppers.
