I would LOVE to explain that claim to an adjuster.

I don't think there is anyway in the world a web could block the lines tight enough to hold that kind of pressure. I would think it would take .5 bar (1/2 atmospheric pressure/7.4 psia) to start collapsing the tank. Do you? You're an engineer. Whadda' ya' think? I just work with vacuum systems alot.

Enough of a plug to throw a code? maybe, yeah?