aeroponic not spraying for 12 hours??

ok i am m pretty sure this guy is out of his mind but i was in a hydroshop yesterday and the guy said i should not have the aeroponic running durring lights out.
he claimed as he said it " you want the plant hungry when thee lights go on.

i could be totally off here but 12 without water = dead plant.

That's crazy! Don't listen to that idiot!