1967
1sr engineer: Hey look, I designed a brake valve block so that when a lower pressure or leak occurs, this piston slides over and lights a light!
2d engineer: Hey good. But, when the piston slides over, why don't you have it cut off the port to the leaking side. That way you'd have a safety factor.
1st: I can't do that.
2d: Why not?
1st: Because 50+ years in the future, a guy on the internet is going to say that isn't how its supposed to work.
2d: What is the internet?
1st: I don't know, but I think in the future, those folks will be smarter than us.
You've never studied how a dual master works have you?
