the reason they didn't give any advance notice is that these bozos would have all got lit the fuck up and some flag officer would have lost even more helicopters, making the US 0-20 this season.
leadership wanted to boost morale for the "special" forces clowns, so they scheduled a gimmie exercise against ghosts while everybody was asleep and then ran away before anyone could get their shirt on and rub the crap out of their eyes.