The nature of the informal implementation of this stuff renders it so toothless, enforcement in whatever form we may see will be pretty permeable. The current CDC cards are trivial to print out on basically any laser printer. ("I have a heart condition so I can't", "heres a picture on my phone"). If you don't have a vaccine you probably just will need to have a test and a temp. screening for the most part.
However the comparison to TSA is not apt. TSA threat model is: One "terrorist" (though I'd call them "premeditated mass murderers") executing its plan is the total failure.
For the vaccine requirements, the threat model is much different. Even if you just don't bother with any of this stuff on %5 of flights, it will still have a great impact in reducing the frequency of aerospace super-spreader events.
Sars-CoV-2 infects a lot of people every day, whereas there are many, many days in a row where no terrorists bother to board a domestic flight.
However the comparison to TSA is not apt. TSA threat model is: One "terrorist" (though I'd call them "premeditated mass murderers") executing its plan is the total failure. For the vaccine requirements, the threat model is much different. Even if you just don't bother with any of this stuff on %5 of flights, it will still have a great impact in reducing the frequency of aerospace super-spreader events.
Sars-CoV-2 infects a lot of people every day, whereas there are many, many days in a row where no terrorists bother to board a domestic flight.