Drivers have no obligation to stick to a particular route. The ride can be refunded if the route is egregiously long or indirect. Even then, if there is a valid reason (traffic, road closure) the ride can be upheld.
If riders are quoted a longer than optimal route, then that appears to be deceptive to me.
If they can take someone from A to B and then not get paid for it because of that kind of rule in how the task is preformed that's highly directed work of the kind you would give an employee.
If you contracted me to install cabinets in your kitchen, I couldn't defensibly take 1 year to install them, if I estimated 3 days. This doesn't make all cabinet installers employees.
3 days or 4 days and you still pay. Uber can't offord a 33% increase in trip length when paying per mile so defacto they are going to have very tight tolerances.
Further the scoring is separately done by the customer. So the conversation is "Can you take the scenic trip? Sorry can't." Further it goes that way because Uber drivers are employed by Uber not independent contractors connected by Uber to customers.
I think you interpret "egregious" differently than I do. You appear to be responding to a set of points I never made, while not addressing the one I did.
If riders are quoted a longer than optimal route, then that appears to be deceptive to me.