Using the Maintenance Mode Scheduler that came with SCOM 2016 is pretty cool but there is no mechanism to detect if a server is already in MM. If we put a server in maintenance mode e. g. for 48 hours and someone else doesn't know this and schedules another MM let's say for 2 hours then the ealier scheduled MM of 48 hours will be overwritten and the MM ends after the 2 hours. So there should be a logic which checks if a MM is already set and how long. If the newly scheduled time period is shorter than the one already scheduled then it will be ignored.