You don't.

That there's one of those parental delusions.

Overheard in New York | Too Soon for a Heath Ledger Headline?:

"Six-year-old boy: Mom, did you know that Elvis Presley died of a drug overdose?
Mom: Well, that won't ever happen to you.
Six-year-old boy, angrily: How do you know?

--Atlantic Ave Station

Overheard by: Jon Good"