frozen@mid80 is welcoming with stories that I have reflected. After you download the program there, the list of net examples in the FindFromList menu may have taken your attention, too. I keep telling stories, for educating your intuition about how a token-roaming in this or that abstract-model may reflect phenomena in the World.
The #2 in the list, is a two-level net. The modifier that is in the shape of a T-transition, is actually a submacro.
That submacro is the familiar net that was in the opening screen (that is, NN73 Fig.2, the #4 in the list, as a free net), mounted as a submacro at that T-transition of the root.
No message/token is roaming through the path that goes through the T-transition within that. Is that a waste?
I had published frozen@mid80 at first, with NN73 Fig.2 as the single example net. That is running well, when a free net. But when that is a submacro, because the peripheral-function is disabled (because the submacro is expecting the framing net to determine the i/o), the criteria for running through the upper path, never get satisfied. I could redefine the functions to fit both the free (or, highest), and submacro cases, but this abstraction is valuable, too.
Well, in the world, waste does exist, although we would not like that to exist. For example, think about a lecturer who is not able (or, not willing) to respond to the questions of the students. If the student may improvise/invent, although a well-thought lecturer could discuss and test that (if this T-transition is for testing/thinking), while the uninterested and/or incompetent lecturer would simply dismiss or blunder. Here is a real-life story.
We may also adapt the story (that I had told) of the satanical situation (which the antichrist, the satan, or KGB, etc. may be active). In that case, the non-activity of the T-transition is a good thing. The framing of that as a submacro, is not allowing the terror events being committed. The jamming is going on, but not being able to act.