Weeeeeeelllllllllll: I don't say it is the right answer, but IDML snippets have the property you are seeking. Snippets that are specified without parameters inherit those parameters from a set of InDesign defaults that are never supposed to change.
Thus, you could construct an IDMS file with your objects and place it using your script.
I am not sure if this would be an annoying workflow for you.
Perhaps someone else would care to offer something better...
Unless I can embed the snippet into my script, I don't it's practical.
Do you think it's possible, at the beginning of a script, to store or save current application and document defaults, resetting them to factory defaults, running the script, and afterwords putting the settings back into place?
You can certainly embed the snippet in your script.
You would have to write it to out to a temporary file from the script
to use it, but that would just be a few lines of code.
Storing and saving absolutely all the application defaults is theoretically
possible, but I suspect is error-prone, difficult, tricky, and a lot more
effort than the snippet approach.