There's a good question emerging here "How do Scouts go about their work?".
My understanding is that the IISS at least only conducts a survey not a census of a planet or system.
A survey is a general view or measurement while a census is an official count of population.
If the Scout's methodology for the survey is to count every habitation from orbit and assign 2.5 sophonts to each that's going to give a Pop figure other than 0 even if the population is transient. However if they do a Neural Activity scan and find 1000 empty habitations that's going to be Pop 0.
Even if they conduct a door to door census, it could return Pop 0 if everybody has gone to the moon on census night.
Scouts might also depend on official figures provided by another agency like the Starport Authority or World Government.
My understanding is that the IISS at least only conducts a survey not a census of a planet or system.
A survey is a general view or measurement while a census is an official count of population.
If the Scout's methodology for the survey is to count every habitation from orbit and assign 2.5 sophonts to each that's going to give a Pop figure other than 0 even if the population is transient. However if they do a Neural Activity scan and find 1000 empty habitations that's going to be Pop 0.
Even if they conduct a door to door census, it could return Pop 0 if everybody has gone to the moon on census night.
Scouts might also depend on official figures provided by another agency like the Starport Authority or World Government.