'Mandatory medical treatment' sounds like a big deal, but the tragedy of the commons happens with every vaccine. No one benefits much from their own vaccination, we all benefit must from others'. Which is why vaccinations almost always have a requirement, or they don't work (cf flu, cf hpv).

When 1500 Americans are dying every day of a preventable disease, it is absolutely reasonable to take feasibility of enforcement into account. And enforcement has to be done where the greatest risk of spreading occurs. People might not like getting carded at a restaurant, but there is a point where lots of people are dying and it makes sense, right? We card for alcohol, we card for driving, and those we do every day.

I would think someone who tested positive should be able to get a ca state qr code. It seems the science supports that. Having each validator check that the test is the right test, and the doctor and hospital exist, seems not feasible, but getting a state qr code - then using that at the point of enforcement - seems practical.