Just wait until someone accidentally burns the shit out of themselves. It actually happens all the time with medical oxygen in hospitals, as in, a controlled environment where oxygen use is expected, and the injuries can be severe, even deadly. Imagine bringing one of these to a BBQ, someone lights the grill too close to you, fwoomp
Me and my dad bought this years ago for backpacking in the mountains. Oxygen levels are lower up there because the atmosphere is thinner. It helps when you are moving a lot.