another example: packing paracetamol in blister packs seems to have reduced suicides.

https://pmc.ncbi.nlm.nih.gov/articles/PMC526120/

> Suicidal deaths from paracetamol and salicylates were reduced by 22% (95% confidence interval 11% to 32%) in the year after the change in legislation on 16 September 1998, and this reduction persisted in the next two years. Liver unit admissions and liver transplants for paracetamol induced hepatotoxicity were reduced by around 30% in the four years after the legislation.

(This was posted here on HN in the thread on the new paracetamol in utero study that I can't seem to dig up right now)