Hmm, I could've sworn that the last time I turned my lights off on my '98 (via the rearview mirror autolamp switch), that all lights were off, then I only turned the fog lights on... not that it's especially useful to do that, I just wanted the headlights off to see where the fog lights were throwing.
I suppose I could be remembering wrong? Seems like the autolamp switch does turn the parking lights off too?
EDIT: I am remembering wrong, just tried this on my '98 and the fog lights don't come on without the headlight low beams... might've been some other vehicle I was thinking of.