I have two valves on the port side under the settee. They are under the small cushion up against the bulkhead. One is the toilet water intake and one is the head sink drain. Any through hull valve or hose letting go is a major problem. Although it seems non-intuitive, it would be worse if it let go with nobody aboard than if it let go while sailing. Sinking at the dock is a real possibility with nobody around to detect it and take corrective action. On the other hand, there is no more effective bailing device than a frantic sailor with a bucket.
If it's easy and cheap (ha ha) to haul the boat out and fix it, do it for sure. If not, could you swim to the through hull and pound a plug in or stuff it with something that would fill the hole?
A few other ideas:
Obviously, the danger is if the hose lets go. Is the hose double clamped? If not, do so. Does the hose look and feel sound or does it feel like the rad hose on a 1974 Ford Pinto? If the hose is sound, double clamped and it doesn't get whacked with stuff while sailing, it's likely OK... but then it's not my boat ...or my family