ward cunningham's checks pattern language information integrity makes it pretty clear: to be meaningful takes more lines than to accept meaninglessness:

Trying to be meaningful:

weightedAverageCost
	| total weight |
	total := self weightedTotalCost.
	total isCurrency ifFalse:
		[^ExceptionalValue reporting: 'N/A'].
	weight := self totalWeight.
	(weight isNumber and: [weight isZero not]) ifFalse:
		[^ExceptionalValue reporting: 'Empty'].
		^total / weight

Accepting possible meaninglessness:

weightedAverageCost
	^self weightedTotalCost / self totalWeight

'Output will remain blank because any other output would be an attempt to attach meaning to meaningless behavior. Users will interpret unexpected blanks to mean that inputs do not apply and/or outputs are unavailable.'