I'm building a kiosk for a client that goes to many trade shows and has a booth most weekends, and if we had a function like get(GuidedAccessModeStatus) would make it easy to set a reminder to the kiosk owner to start guided access when setting the kiosk up for the day.
Further, you could use the status to conditionally hide a button that takes the kiosk owner away from the Kiosk layout(s) that is not visible while guided access is running, thus preventing kiosk users from getting into layouts that aren't for their eyes. Right now I'm relying on either hidden buttons or brute force (i.e.: end guided access mode, then double tap home button and force quit FM Go, then reopen the file which defaults to a kiosk owner "kiosk setup" layout and not the actual kiosk layout that is for public view) to get off of the kiosk layout(s).
The Guided Access function of iOS is VERY helpful in developing FileMaker based kiosk applications. It prevents the iOS device user from escaping the currently running program. By adding the ability for FileMaker apps to become aware when that mode is enabled and running, in the iOS operating system, a whole new world of functionality could be added to make Kiosks easier to use for users by allowing more granular control of what layouts can and can not be navigated to based on the on/off status of guided access mode.