Unlike proper buildings, there is no "safe zone" around decorations, bombs, teslas and traps.

Safe zones are the space appearing in white around buildings when you move them: no troop can be deployed inside this zone.

You need to consider carefully where to place your traps and decorations. If you place them outside your village or too far away from buildings or walls, they will create a gap and opponents will be able to deploy their troops right on top of them.