Thanks Steve -- I just checked my Speed Graphic -- and yep, there was tension on the focal plane shutter. Now released (after years of being under tension). It is a little relunctant to go from 1.5 to T and T to 0. Should one set the spring tension at any particular setting during non-use (mine has 6 spring tension settings)?
I've always left mine on "1", maybe it is an old wives tale, but that is the advice from the old timers, like on Graflex.org. It is easy to adjust if they do go off, though.
I find that the opportunity to experiment is one of the great by-products of mistakes like double exposures. When I realize I have botched a roll or holder, it gives me complete license to do what I want with that roll or sheet... new developers, new twists in my processing rituals, etc.