A Bug's Life

A Health and Safety Officer explains: The fourth wall is there for health and safety reasons. It prevents unseemly metaphors leaping off the stage into the audience's consciousness (assuming the audience is conscious), as per the Health and Safety (Taking Things too Bloody Literaly) Regulations 2007. The fourth wall, like the fire curtain, must be lowered at every performance.

A former art student and parent adds: the fourth wall is both erected and breached at a very early age now. The excellent Canadian animated series THE BACKYARDIGANS repeatedly contains lines that only make sense if the audience is joining with the characters in the joke such as "that certainly is convenient" when the deu ex machina appears, and works because the quality of the writing enables one to switch easily between modes of watching. Children's first experience of live performance is then most often a version or compliation of the stuff they've seen on Cbeebies and Nick Junior that compounds this. They don't necessarily understand intellectually but find the discontinuity very funny.

Also: you've appeared in various stuff at conventions)as have I). It is a necessary mental constuct when performing to enable one to stop thinking "Oh Shit! they're all watching me!"