I once drained the transfer case on a Chevy and was interrupted by an unexpected old friend showing up. Ended up taking him into the house and talking (beer involved). I did not mention to my wife the truck fluid draining. She went out for some snacks and more beer and yes, she took the truck, not noticing the pan underneath. Fortunately it was not the engine oil and all was well with that truck for years afterward. She still drives a truck.