Safety issues are one thing (and should be a matter of legal regulation, not individual corporate policy) but performance issues are another, and I've already seen them conflated in this thread. Should my employer have the right to impose a curfew on me so that I'm not tired the next day at work? Should they have the right to attach a tracker to me to make sure I'm not cheating?
We are already flirting with corporate-employment-as-citizenship and crazy dystopian things have become status quo, e.g. beyond-the-pale noncompetes for leaf-level wage-slave class employees, and all "inventions"/IP developed by employees in their own time belonging to their employers regardless of relevance to their employer's business or support they received from their employer in developing them, and so on.
If an employee is performing poorly, fire them. That's where this should start, and where it should end. People are already selling their time to their employers, and they shouldn't have to sell their souls too.