Source: Elines

All Flight Attendants are automatically opted-in to allow other Flight Attendants the permission to view their schedule.

If you wish to restrict the ability for other Flight Attendants to view your schedule, in CCS select the drop down arrow by your name in the top right corner of CCS, select General Settings > Schedule Opting Electing (under the General Settings menu on the left) > Restrict> Update. 

Once a Flight Attendant restricts their schedule they will be restricted from viewing other Flight Attendants schedules.