This may warrant an entry in the bug base, I'm not sure.
I had forgotten about this until today.
In a city my group owns, Andolini on the planet Douglas VI, I built a garage next to an existing power generator. The garage did not violate the 2-sides rule. However, when the construction was started and I looked at it later on, the generator, after starting, does NOT have 2 sides clear anymore.
Does the check only get done when a building is built?
If the admins want any additional information or want to fix the garage, put it elsewhere, that's is fine. There's plenty of room in that city. Just give me me a heads up that its being done.