Still Kicking
Contributor
You make a point but it is an argument for always analyzing your gas, not trusting that the gas is what the provider says it is.Whenever I see this statement I shake my head because upon deeper analysis it makes no sense when viewed in isolation.
If you're diving a rental tank from an op that also supplies Nitrox, you are incurring a similar risk in that you could very well be diving a tank full of nitrox and are exposed to potentially more danger than getting a nitrox blend that is a bit different from what you expected.
Yet air divers are not trained nor expected to analyze their air tanks.