Guard towers for SHTF

Those of you who may have been in the military like me and may have spent many a hour in one of these death traps, know the inherent dangers they pose to the poor bastard(s) in them.
You are a sitting duck waiting to be taken out by a highly trained or lucky riflemen. There are many more ways to post guards for early warning defenses along with actual early warning devices like trip wires attached to noise makers or flares, or explosive charges, etc.
Also taking higher ground than your surrounding area provides a much better vantage point to see someone or things coming at you with far less exposure ! Thanks but no thanks to guard
towers !