The magic SysRq key is known for linux users to perform some actions when the system freeze , but it considered as dangerous command for users who have a physical access to the system:
Some people view this key as giving access to dangerous system-level commands to anyone who has physical access to the keyboard or serial console. It has been argued that this perceived security risk is illusory, as anyone with physical access to the computer would already have the capability to compromise its security. The advent of the procfs interface has rekindled debate over this subject.
How can the Magic SysRq key be dangerous for linux users ?