Just for fun, here's the sign near the lake. It says something like the following, though I don't think I have the "eat a campfire" quite right.
Usage regulations. Resting place.
Please let order and cleanliness prevail. The provided firewood can be used for grilling. It is forbidden to eat a campfire or burn it unnecessarily. Please do not throw any objects into the lake. Swim in the lake at your own risk. Take your rubbish with you and don't leave anything lying around. Parish of St Niklaus.