I figured I'd share my story of stupidity for all to enjoy:
So I haven't backwashed in quite a while (over a month) and my pressure gage is suspect (the face came off and the needle indicator is open to the weather), but I figured since I'll be closing next weekend and tearing apart the filter for a thorough cleaning, I could probably limp along another week -- WRONG. I was right next to the filter, fiddling with the diverter valves when the seal let loose on the filter housing and I got a spectaular cold shower. My wife came running out when she heard me screaming like a little girl but then had herself a good laugh at my expense.
Needless to say, the filter got a tear-down and a full cleaning a little sooner than I was planning and I guess a new pressure gage will be on the to-do list for next spring (I would love to know how high the pressure got before she let go). I suppose that while it wasn't pleasant to get a cold shower yesterday it was probably a good thing I was right there to shut the pump off. Can't imagine the fun I'd be having right now if it happened unnoticed during the night or when I wasn't at home.