When I was little, there was an advert on the telly for Chambourcy chocolate mousse, that had the slogan "Sh! Don't tell the children!" to suggest that it was so yummy that they'd eat it all before you got a chance to have any.
My sister thought that adverts were subject to the watershed like TV programmes, and believed that the Chambourcy advert had slipped through mistakenly when it was aired before 8pm!
A childhood belief about adverts

others believed things like this
- When there was an advert for a "3 peice suite" i thought it was a shop selling 3 P Sweet's!!!— Kate Parker
- I convinced my sister that chocolate milk was made out of Keebler cookie elves, she believed me for a month— Rainbow Steel
- Chocolate, they say, rots your teeth. I believed if you drank chocolate milk, your bones would be brown.— Dellio
- I thought Warner Bros was a cop drama that aired on CBS at 10:00 PMAnon
- I believed you could dry your hands with hot water, until i got a chance to try it.— A A RENN
- my friend thought that the film 'the hulk' was about the jolly green giant from the sweetcorn adverts.— patticus