Oh yes,  what a great thought.  I had that lock feature on my old film cam, too.  But, in order to choose mirror lock up on the D70 I have to go to the menu and manually select it in three steps.  There doesn't seem to be a way for it to be chosen randomly or by accident.

Thanks so much for your reply and for that idea as I will keep track of my menu functions now.

Jodie

I kid-proofed my house but they STILL get in!!