Laws are merely barriers to work around, incentives guide what's going to be attempted. Making something illegal adds some negative incentive, but isn't nearly as good a solution as simply having positive incentive to do the right thing.
What makes you think laws aren't incentives? "Merely barriers to work around" kind of misses why laws exist in the first place. Making something illegal is what society should do if we collectively agree that behavior is to the detriment of society without any positive gain. What do we gain by allowing drug manufacturers to put false expiration dates on their products?
