Moreover, the diversity among the traps was too high for them to remember all the signs or look out for all of them at the same time.
There were ambushes by automated drones from the sky as soon as someone tried to invade past the programmed range; minefields just under the surface of the ground that sometimes even the sensory mages were too late in finding and reporting but the worst of them all were the proximity mines that exploded in succession without giving them any warning or reaction time.
Since the forces were spread out due to their huge number, the warnings usually came a hair's breadth too late even if the sensory mages managed to recognize the telltale signs very early on.
As a result, the inevitability of losses became an unfortunate reality, a bitter pill to swallow despite the meticulous planning and precautions.
