I think pre-emptive enforcement of something like this is extremely difficult without getting downright creepy and invasive. The best you can do is drop the ha

I think pre-emptive enforcement of something like this is extremely difficult without getting downright creepy and invasive. The best you can do is drop the hammer on anyone greedy and dumb enough to get caught - and I'm sure there will be some of these! But personally, I prefer vaccines where the chain of custody didn't require massive bribery and risk-taking.