It’s along the same lines as the temperature checks and health screens, looks good on paper and in the media but provides very little real benefit.I see a burgeoning black market for counterfeit test results- or "labs" that pop up and offer guaranteed results.
The time share hawkers and cruise ship remoras need a new hustle, this is perfect!
I have had to show negative results for travel during the pandemic, and the checkers often barely glimpse at the paperwork. As long as the names match, the results are negative and the dates are good, everyone got the red stamp.
Not saying this is right or wrong, just observing that a system/process is only as good as it's controls.
The time to lockdown international travel was January/February when it might have had a real impact on the spread. That cat is out of the bag. The effort now seems to be preventing the spread of variants but I have a hard time seeing how this broad approach will help when a more focused but intensive restriction could target the problem directly.