Hi @DougWalker ,
Thank you for posting on the Instructure Community!
Regardless if the button is enabled or not via the course navigation, all students are able to access their course grades by clicking the 'View Grades' button on their dashboard page. While teachers have the option to "disable" the button, it actually just hides it, as teachers can't disable the actual gradebook inside of Canvas. Students can still add /grades to the end of the course URL to view their grades in any course. This applies to computers / laptops.
When it comes to the Canvas Student app, however, the only solution I have is to require teachers to enable the grades button in all of their courses in order for the page to not be disabled. I'm honestly unsure why the behavior between the app and the desktop are different, but that would be the one solution I have.
I hope this helps a bit, reach out if you have any additional questions or concerns! We're happy to help.
All the best,
Noah