I've been doing some of this involuntary labour stuff in my game with some conquered NPRs and have built up to 6000 mining camps over the course of a year on one planet. 20 well trained police group of 1737 units was able to somehow control the entire 3bn population - the lowest point being 85% stability.
You can then ship these with impunity (thanks to civilian shipping) all around the empire without any further consequence. It seems weird that the presence of people being "reeducated" isn't really seen as an issue to the rest of the populace or even the victims themselves.
I think it should be handled race-wide, species to species basis. Species with high xenophobia care less when camps built from other species in the empire are present while xenophilic species should care exponentially more that some are being pushed into work camps. Of course like with how policing requirements are tracked militancy should also matter.
Right now these camps are incredibly strong, especially in the mining context - you can have 10 times the mining with camps as opposed to paid miners and this ignores the 1/3 building cost/time.
The draw back of transportation makes sense and helps but somewhat dissipates endgame when like in my game you have around 300 civilian transports meandering about.
I do like to ship out 1000s of construction camps to build artificial moons though
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