Not quite the same,but at 5 my eldest memorised the pin on the interactive TV , andordered £70 worth of movies for us.We were not pleased.Last year,aged 9,he hacked a schoolfriend's email account and used it to send malicious emails to two ex teachers from his school.
We have our pc on all the time,we use it lots.Matilda's regularly resetting things.She adds those gadgets when you see the clock or slideshow pictures at one side.Her most annoying trick is rotating the whole screen so no one can use it.