Trivial The oxygen vendor will still charge you for adding no gas to a tank.

[Avack]

Put a gas tank into the vending machine. Fill it. Continue to press the fill button. You will be charged repeatedly but no oxygen will be dispensed since the tank is full. When I tried this, I was charged 607 credits on each occasion and completely drained my account.

[Mordent]

You ever tried filling up your tires at a gas station? Feature, imo.

[Flourish]

This is intended behavior, so it would be a feature request.

[elan_oots]

To be clear, what it's doing is *replacing* the air in your existing tank with fresh new air. I figured you wouldn't want to just top off an existing tank if it had impurities. It seems like it'd be pretty easy to either display the air contents in the air vendor so people don't do this, or check to make sure it's not full of pure O2 before replacing the gas. Either way, like Flourish said, this is intended behavior.