Hardcore Breakfast discussion...love it. That sound is definitely the CMSS cue, and thus the start of the song. So as Dave said, if it starts with that, CMSS. If they jam into that, then jam > CMSS. I think things may eventually develop into more plain CMSS with no jam notation. The jam just becomes an understood, an assumed part of the song that is engrained into the song. Think of Phish\'s jams into David Bowie, DWD, Ghost, and Maze. All very, very similar. But eventually you never saw jam > before those songs because the jam became understood.
Now that I think about it, seeing DWD > Ghost > Maze > Bowie sounds pretty good right about now.