Some macro names have the addition vetoable. This indicates the ability of a macro developer to suppress standard functionality.
You can define a macro that starts, for example, a semantic check automatically when a user saves a model. The semantic check is triggered by the Model is to be saved (vetoable) event. To suppress the save operation for non-compliant models, you must include the line Context.setProperty("event.veto", "1") into the corresponding statement block. The model is saved only if the semantic check rules are met.