If a government makes it mandatory, then the government must and should have put something in place to accommodate this.
You can only mandate me when you know you have given me the capacity to handle such a mandate. For example, a government that knows and can boast of its citizens' financial capacity can mandate such and should be from the perspective of love and care for its citizens.
A government has every right to mandate regular check-ups because its citizens are its asset. They are its primary subject and the reason there is a government
The citizens affect the economy in a very large percentage, and so a movement which has economic growth and and the development of its people will do everything to put its people in good condition, and this includes regular medical check-ups.
Some might say it is simply trespassing, but it is not. It is true that it may appear even worse in a country that is not a communist, to impose regular check-up, but it is a national responsibility and governmental to mandate regular check-ups.
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Regular check-ups can also help in discovering terminal diseases that could pose a threat to a whole nation, aside from even being a threat to the existence of the one bearing the disease.
Regular check-ups would help in preserving the labour force and work force, whcih in turn adds to the economic growth of a nation.
And so, as a matter of national survival, growth, and development, government should mandate regular check-ups, but not after it must have given its people a good life.