Jay has posted this important information over at the DG. For any of us that use any type of map editor, this is a "must read".
Exhibit fences 1 tile away from map edges can cause crashes
Tanks do not deteriorate or need maintenance men part from for the filter so I would say not. Tanks against walls when one tile out create another sort of problem that we can live with. Just looks a little funny. The first two screens are against the wall. The next one is one tile in.