Would it though? How different is that than life in prison without parole? There are plenty of people who, given the choice between ~$1M and a ~1% chance of the death penalty, are going to pick the money.

You could hypothetically try to make the difference in the penalties larger by making the penalty for selling to adults smaller, e.g. a $10 fine, so that there is minimal incentive to pay for countermeasures when selling to adults and thereby have them already paid for and in place when selling to kids. But then you're just de facto legalizing selling to adults and trying not to admit it.