"Santa sees all, so behave"
"If you misbehave you go to hell"
"Don't sit too close to the TV or you'll go cross-eyed"
"Masturbating makes you go blind"
"Respect your elders because they are more mature/knowledgeable"
Basically we constantly lie to our children.
How'd your child deal with their friends believing in Santa and them knowing it's a hoax at that early age?
- What do you think, dear?
Followed by discussion of the evidence... if all goes well they learn to use their own judgement and cope with coming independently to their own conclusion in opposition to 99% of their peers...
"A lot of other kids really enjoy the Santa game. So don't spoil it for them. Like when you're playing being a pirate captain you don't like it if another kid says you're too young to be captain or your cardboard pegleg is fake..."
Kids more easily accept games and makebelieve, and happily hop into different games.
(2 kids, 4 3/4 and 2)
So we still do presents from Santa at Christmas, Easter Bunny baskets, and Tooth Fairy money, but they know it's us doing it. So far it still seems to have enough magic of anticipation that they enjoy it.
And let's face it, Santa works pretty well as a cryptid alongside the tooth fairy and the Easter bunny... :)