If you switch to edit mode, make radius 10 of placing Inaccessible terrain and click next to a city, its non-central workers remain where they are while the city just can't work Inaccessible. Did not check border changes by editor, probably they are correct.
If you switch to edit mode, make radius 10 of placing Inaccessible terrain and click next to a city, its non-central workers remain where they are while the city just can't work Inaccessible. Did not check border changes by editor, probably they are correct.