What I was thinking of when I mentioned 'hidden POP' was the situation where a system has it's capital located on a low-POP world but there's also a hi-POP world present. Think of the StarTrek TOS episode 'Cloud Minders' only with separate worlds.
However it came to be, there is one apparent example from the CT supp covering the IN in the S'Marches.
In the entry concerning the 'monitor' (no j-drive) constructed from a planetoid, it is stated that the system of Rorise purchased it from the IN for system defense.
However, according to the info in the CT 'Spinward Marches' supp, Rorise has a POP so low that there's no way it could realistically support manning the crew!
I came up with a number of rationalizations over the years, w/o actually going back & reading the rules, until, years ago, I posted the info on this list.
Immediately at least three people responded, reminding me that the basic system data ONLY applies to the 'main' world, & not the whole system so there could be a lot more POP out there. Could be a another planet w/ a higher, even much, much higher, POP or there even could be a number of planets/planetoids/whatever w/ lower POP's that all add up to a much, much higher population than the 'main' world.

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On Tuesday, August 18, 2020, 09:25:50 PM MST, xxxxxx@gmail.com <xxxxxx@gmail.com> wrote:

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It should be rare that the supposed mainworld has no port and where another high pop (or even mid pop) world with ports exists. One would think TAS, SPA, IISS, somebody would get the mainworld changed if that happened so as to deal with the biggest/best part of an active system.

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