"But seriously, do the lacies use inactive mounds, or only those still inhabited? I m sure the scent would play a role should it be the latter. Of course a spritz of formic acid might do the trick.....don't know what the lacies que on."

They only use active mounds, because for this species the whole point behind using the mounds is the heat and humidity provided by the termites. Termite mounds are nature's nest boxes. The protection offered by the mound itself is secondary. Females will dig into a dead mound but stop short well before hitting the centre because the temperature and humidity levels are all wrong for nesting.

I suspect they use visual cues to find the mounds, as they stick out of the landscape like the proverbial dog huevos