I like the idea of having an actual 'carefulness knob' prop and making the manager asking for faster delivery/more checks actually turn the knob themselves, to emphasise that they're the one responsible for the decision.
Yep. The best way to pushback is to ask your manager, "We'll do it fast since you are asking for it. What is the plan for contingencies in case things break?"
I don’t think the manager needs a button to remember he’s responsible for the decisions, usually it’s the other way around, devs having to remember they’re not; I’ve been too many times the manager putting it on zero only to hear, “You can’t do that it has to be at least a nine !!!”.