Where do you find such people? How much do they cost? Are there high-end and low-end outfits that employ them?
How big do the cakes tend to be? Are there any specifications for the decoration? What's the inside like? I assume the cake is built around some kind of inner container that the person hides in; what would it be made of? Do they just get out by pushing the lid up? (Wouldn't that dump the top layer of cake everywhere?)
Anything else I should know?
Modern day, present time, real world, so there's nothing unusual to take into account. I've seen it in movies, but they tend to be from the point of view of the partygoers, not whoever sets it up. And I'm hoping to find information about seamier setups (assuming there are such), which I am terrible at doing first-hand research on.
All help is appreciated!