Why do some countries have inconsistent rules about PCR?

Question

E.g Georgia.

You are fully vaccinated. If you want to enter by plane, you don't need a PCR test.

You are fully vaccinated. If you want to enter by road, you need a PCR test.

Why?

Answer 1

Because the people in charge decided it should be that way.

Covid requirements and rules are notoriously complicated and inconsistent all over the world. They are made by people with various levels of skill and understanding and with surprisingly little co-ordination across different departments, countries, states or even counties. A lot of these rules are also politically motivated and the political goal often overwrites any type of rational thinking.

A simple example: I was applying for exemption from quarantine and was denied because they didn't like the specific test I had. I moved one mile away to a different hotel (just a different administrative district) and they accepted the exact same test without any issue.

Answer 2

Multiple reasons apply:

1. From a physics/fact-based perspective, those vaccinated for COVID (or any other disease) can still be infected and can still spread the virus to others. Depending on how you measure things, they're 2-10x less likely to infect others than those without a vaccine or prior infection but they can still be carriers of the virus. Hence a PCR/antigen/NAAT test can reduce the number of infected travelers entering the country.
2. Travel has been blamed for the spread of the virus since February 2020 and international tourism in particular is still seen as the biggest culprit. This of course made perfect sense back when the virus was confined to a few cities in China but the logic broke down once the virus spread to every other nation. For example, the US has had tens of millions of domestic COVID cases but plans to keep restrictions on travel from the EU until November 2021 at the very least. Requiring a PCR test for entry is a way for the country in question to "save face" by making it look like they're not just "opening the floodgates" for international travel.
3. Tourism is seen as a "non essential" activity and there's a certain taboo on doing "non essential" activities during the pandemic. Some continue holding this belief despite vaccinations being widely available in all developed nations. The PCR test requirement thus serves to discourage engaging in "non essential" entertainment.
4. Where tourism is important for the country in question, they may choose to relax the PCR requirement just for the "wealthy" tourists who are likely to contribute a lot to the local economy. Those tourists are likely to fly-in vs. cross overland, so this would explain Georgia's differentiation on land vs. air borders.
5. Don't discount the effect of "we've always done it this way" and "other countries are all doing it this way". Its hard to get rid of a travel requirement once its been in place for a year, just like we're still taking off shoes in some airports or can't take a water bottle through security.
6. As explained in our question on the cost of public transit to airports, most voters either don't travel much internationally or don't particularly care about international travel. And obviously tourists themselves are not eligible to vote, making it easy for politicians to introduce various restrictions on travel without fear of repercussions.

At some point all countries will follow Mexico's lead and stop requiring PCR testing prior to entry but this will likely take many more years, especially for zero-COVID holdouts such as Australia. I took my 10th COVID test this very morning for a trip to Canada and it felt completely routine, just another small thing you have to do to enjoy the wonders of travel :-)