It's so easy to use lube, it never occurs to me not to. Big Ziplock bag, half full with wet-cleaned, decapped brass, a squirt of the RCBS water-soluble liquid, knead for a couple of minutes, and hey Presto! Dump into a clean stainless bowl, and start sizing. Rinse sized cases with hot water to remove lube, let dry, then prime.
Dry tumbling has been eliminated from my shop due to the airborne lead dust issue. If you're counting on the residual dust from the dry tumbler to lube your cases, then you're getting that lead dust on your hands.