Like others said and speaking of this topic, once in awhile I've gotten off at Glenview instead of downtown Chicago on the Hiawatha(Chicago-Milwaukee) going back south. Honestly on that train, I get the sense the employees/conductors generally don't care if you choose to get off early, before your final stop without informing them. If I was in business class or a sleeper on an Amtrak train, I'd probably give one of the employees(either a business car attendant, or sleeping car attendant) a heads up that I was getting off early, so that they could briefly check around that seat(or roomette or bedroom if it's a sleeper) before arrival at the final destination station.