What are staff still forgetting to do with company cars?

Six: What are the staff still forgetting to do with company cars?
[pause]
Man: . . . and I see there are still problems with staff borrowing company cars!
Woman: I sent out memos reminding them to write down how far they’d driven.
Man: Mmm, that’s fine now. I wanted a car for an important trip last week, though, and there was no fuel in it. Staff know they mustn’t leave cars empty. But at least they do tidy up inside them now.