Sometimes I believe they do think the audience will ignore it.I would certainly like to think so, but I think that it needed a simple, throwaway line of acknowledgement, rather than hoping the audience ignores it.
I CAN remember one time they did throw in a little line in a nod to continuity. I guess it was in Macrocosm, when Janeway and Neelix have came back onto the ship and can't find anyone. Neelix has been stung/bitten already. Janeway scans him and says "Your lungs are filling up with fluid". He reminds her, "LUNG, captain". Now see there writers, that wasn't so hard, was it?