If a planet is listed as having no controller/government but is in a system that is controlled, do I still need build permission from the system controller?
Is there any chance of slab decay being implemented? If an area was cleared but nothing built on it, after a while it will need clearing again in RL, but as I see it a lot of planets get slabbed but with no buildings ever put there.
When a planet is not controlled, the system controller doesn't need to give permission to "build", often times most people chose to slab it and build later because slabbing a planet is almost a rarity and can often bring in the most income. But you can build on an empty slab if the planet is uncontrolled. If you are building in empty space in that system, then you'd need permission from from the system controller.
Almost forgot, if you are the owner of the slab and you want to build on a planet controlled by another group, you can still "Build" there, but they could arrest your builders, edit: as they will receive an event notice that you are building on that slab, however if memory serves me right, if the city is hidden they may not get the event.
Just to try to clarify things, I will try an example:
Planet X is uncontrolled but every square of the planetary grid has an empty slab on it with the exception of 1 or 2 small cities.
I can just build on the empty slab, even though it's owned by someone else. But, if I start to build something, the owner will get a notification. Is that correct?
How could I build a hidden city on someone else's slab? That doesn't sound right.