Check for files NOT changed.
Per my question, check that a file has NOT changed before executing backup program. If file has changed then do not run backup program.

You can achieve this by combing inactivity events with include filters.
In simple terms, specify include patterns for files you want to monitor inside a directory (https://deventerprise.uservoice.com/knowledgebase/articles/196135-exclude-and-include-patterns). Do not select any specific event types and enable the option to “Generate and event when there are no changes at all after X amount of time”. If there are any file that change for any reason that match the pattern, the inactivity time will never be reached. If no changes are in the given time frame, an event will be fired indicating the file has NOT changed in the given time.
You can setup a second monitor with the same include filters, but this time select specific events that you would like to see (modified, deleted etc). In the rest of the configuration of this second monitor you can trigger anything you want if the file that match DO change. The two monitors can react differently even though they are watching the same directory/files. Inactivity can trigger certain things and activity can trigger others, just depends on how you want to set things up.