It's even easier than that: quarantine any ship that has made port in the last 2 weeks and the crew was allowed to disembark and let any ship with no sign of di

It's even easier than that: quarantine any ship that has made port in the last 2 weeks and the crew was allowed to disembark and let any ship with no sign of disease where the crew has been onboard for 2 weeks to disembark. Then, the crews can disembark at least every 2 weeks, and it's pretty simple to verify whether a ship has allowed it's crew to disembark; check their port logs.