It's a good theory. There are many reasons you'd want people to believe your population is greater than it is, and few incentives to keep the numbers low, or at least to publish low numbers. It's one reason why Trump fought so hard over the census - statistical surveys would basically create a system of incentives cheating for congressional dollars and seats, and counting illegal aliens (which are inherently difficult to pin down accurately) would do the same thing.

Internationally, I don't know of any organization that would verify the integrity of the numbers. OTOH, while I think that there must be some UN and IMF programs that spread money out according to population, it just sounds reasonable, I don't know if they actually exist.

It's a good theory. There are many reasons you'd want people to believe your population is greater than it is, and few incentives to keep the numbers low, or at least to publish low numbers. It's one reason why Trump fought so hard over the census - statistical surveys would basically create a system of incentives cheating for congressional dollars and seats, and counting illegal aliens (which are inherently difficult to pin down accurately) would do the same thing.