You might not be able to use the SETUNGUARDED method or UNGUARDED option in all cases. A method might need exclusive use of its object variables, then allow methods on other activities to run, and perhaps later need exclusive use again. You can use GUARD ON and GUARD OFF to alternate between exclusive use of an object's scope and allowing other activities to use the scope.

By default, a method must wait until a currently running method is finished before it begins. GUARD OFF lets another method (running on a different activity) that needs exclusive use of the same object variables become active on the same object. See Section 2.9, “GUARD” for more information.