Why does the tradition expire at noon?
That feature probably relates to the customary boundaries of the old renewal festivals, which limit the mayhem to a very strict timeframe. The source of Britain's deadline might be the 17th century's well-named Shig-Shag day, when celebrants put oak sprigs in their hats to show loyalty to the monarchy, in reference to Charles II's hiding in an oak tree. Those who failed to observe the custom could only be ridiculed until midday. These days, anyone who plays a prank after noon is supposedly an "April fool" themselves; this nice observation may not seem so crucial to anyone who has been custard pied at 12.01pm, but it distinguishes our version of the ritual from that found in other countries.
'nuff said
AU Projects: | Banbha et al. | New England: The Divided States Blood and Fire
There was once I (in conjunction with a guy in Australia) pulled a Prank on a message board from Midnight Australia time to Midnight Alaska time (we had a member from Alaska on that board).
That was a lot of fun - we had people convinced that it couldn't be a joke because it ran for so long.