My son just returned from camp and informed me the propane tanks were empty. WHAT? I just filled 2 100lb bottles in early spring. I secure the tanks for stability but don't lock then in any way. Looks like the tanks were replaced with 2 empties. Sounds far fetched, but the regulator was attached but the chain used to keep then in place was not. This is a new one for me. Never had any problems before.