Clock correctness is relative. If the antique windup clock in your living room is off by 5 minutes, it's still basically right. But if the clock in your smartphone is 5 minutes off, something has clearly gone wrong.
Nor is it only incorrect one billionth of the time, as you seem to be indicating through your hypotheticals. Depending on what I've asked it about, it can be incorrect at an extremely high rate.
