I'm South American. Every time entering the kingdom, I need to show my yellow fever vaccination card. If I'm not able to show it, I will need to be vaccinated prior to immigration.
Today I have read an American went to immigration ( can't remember which one) with printed email and they told him he needed to have one sent by mail by his embassy, and they were still not able to process his requirement.
He said he started to be pushy, but officers there seemed not interested in working, so he preferred to hold.
When I read this, immediately I thought about a new amnesty.