The tea bag is a perfect example of the problem a law would need to address, and it is not always clear cut. A consumer is certainly reasonably interested in the price per tea bag, which s/he accepts as a proxy for a single cuppa (and of the strength that consumer wants which is a variable in itself). Vendor 1 could have more tea per bag than vendor 2, but would vendor 1’s bags make more cups of tea (of “the strength”) in a practical sense, as packaged? If each bag had a multiple of the tea weight, yes, otherwise probably not and the bag would be thrown in the garbage after one use. Those who like weak tea would use and evaluate bags differently than those who prefer strong tea, but the cost per cup is still relevant.
To resolve that the unit pricing would need to include both price per bag and tea per bag, not unit weight cost of the tea. (Unit weight cost of the tea is economically interesting but in a practical sense is it meaningful for the purchase of tea bags to make cups of tea?)
