I've just published an article in regards to suppressing triggered scripts when user/script initiated. The blurb is as follows:
Script triggers are a great feature in FileMaker that allow you to initiate a script when certain actions occur such as committing a record or leaving a layout. Not only do they run when user initiated, they can also be script initiated by script steps. This can sometimes produce unexpected results and so you may wish for triggers to be disabled. This article presents a very simple and elegant method of suppressing script triggers from firing when initiated by other scripts.