The “might work” is doing a lot of heavy lifting in this sentence. How strong must the evidence be for the hypothesis of efficacy to be considered reasonable?
Do you doubt there are people who refuse to accept the consequences of their own actions and seek to place blame anywhere else they can?
Or indeed some third party might do the claim with hindsight. Prosecutors or whatever. People can be irrational, in general.
It would require legislative bodies to pass laws against the wishes of the people. Maybe in China :)