what's the lowdown with system members? when should you use them, when should you avoid them? currently I'm creating and storing these values as attributes in the object. “owner” seems like a weird term. Owner is “created by” if I am right? just a bit confused why and when to use these vs modeling it out (also in the domain model you get to see the association lines, which can be helpful) Edit: Owner on NPE temporary attributes seem like it might make sense?