Schedules are used to set availability start and end dates, and due dates for all the units and content items. Availability dates determine when content is allowed to be shown to students; however, when using system-to-system authentication, the application needs to determine how to restrict content access.
It's important that your application respect the dates defined in a course, both for content and for course access itself. With only a few exceptions (notably, the Grades API), the APIs do not restrict data based on dates. If your app does not respect the dates defined here, it is possible it will give some students access to resources not available in the User Interface, disrupting the planned schedule or giving an unfair advantage.
If your app leverages inbound single sign-on to launch or deeplink into a course, you must be sure to check the start and end dates of the course itself. The SSO features allow access to courses regardless of the access date restrictions.