RouteMaster gives you access to router lock and protect functions to prevent important routes being inadvertently changed. You can do this right-clicking in the crosspoint display.
Locked routes are highlighted in RED.
Protected routes are highlighted in YELLOW.
Note: The behaviour of lock and protect varies between routers. RouteMaster issues the corresponding commands but exactly what the router does will depend on how the manufacturer has chosen to implement these functions. Refer to the router documentation for more details.