In general, this principle works for lots of things. Drug use at your office job? No problem so long as I can’t tell you’re on drugs. And so on and so forth.
The alternative isn’t some clean job. It’s where people who are incredibly stupid and scatterbrained have a “reasonable accommodation” and then you’re on a plane run by a fucking moron so that when the other competent pilot falls ill the moron will have to fly it by himself and then you all die.
You thought you had 2x redundancy? Well one of the machines was always failing. No thanks. Let’s keep doing what we’re doing.