Ha! I am glad it was not me! It could have been though. One year I launched with the valve for the head's overboard discharge open (for others reading in Canada it is illegal to plumb to this valve so it had never had a hose installed). I happened to be present at launch and heard the water making a mess of the forepeak. 10 seconds and the valve was closed but had I not been present...
The problem for the Contessa is that the cockpit drain seacocks are virtually inaccessible if you need to get to their seacocks in a hurry. I would have to notice the problem (i.e. water over the floorboards), not panic, find a screw driver (lockers are filling from below now), remove the cockpit floor panel (with so much water inside the boat the cockpit sole is now below the waterline so the drains are back-filling the cockpit) and then close the valves (which are now under water) -- all while more water rushes in faster & faster! I would be sunk before I got them.
And of course there is the underlying assumption that someone is around to notice if I am not there.
I think that the real value of seacocks is the convenience of replacing hoses or related fittings while the boat is in the water. BUT, if you maintain your boat, if you inspect, if you pay a little bit of attention, your hoses should be totally reliable. And if you must have seacocks, put them where you can reach them in a hurry.
I was on a big Hunter last year and noted that all the plumbing was led to one area in the middle of the cabin sole. It was done for the builder's benefit since he could install all the through-hulls on a panel on a bench and then install them in the boat all at once. From the user's perspective, it meant one stop shopping. One area to check, one area to maintain, one area to run to if there is a problem. While this is not practical for the Contessa, if I were determined to have seacocks and if I was prepared to re-locate the through hulls, then I would relocate the valves to the area between the batteries and the cockpit sole. At least they would be in a place where I might be able to use them in a hurry.