Countries are sovereign, and they decide who they allow to pass in (and even out!) or not. The COVID-19 crisis underlined this even more. If you want to live with little to no restraints in a foreign country, become a (good) diplomat/spy. Which is limited by supply (and kind of like a tradeoff with the target country).<p>Yes, ideally, this world would be a peaceful place, with no military, no terrorists, no dangers, no security risks, no blackhats, no drug addicts, no gangs, no children military or selling drugs, (screw all that just no crime/violence <i>flowerpower & peace sign</i>) etc etc. But in the real world, all of this exists, and a whole lot more. That's why not everyone's allowed. Then there's the economic difference between countries, and power differences. The rich countries want to stay ahead of the curve, and the poor countries want to step up. Any propaganda to reach the goal is warranted. China uses different techniques than USA or EU. Much more authoritarian, for starters. Remember what I said about diplomats/spies? Your proposal would open the floodgates.