After more throught, I realize I'm wrong. For a new script, the Defualt GUI is GUI #1. Therefore, you wouldn't lose reference to it. As far as if creating a New GUI should make it default, I think it should be consistent whether it has a Name/Number or not. In either case, I don't think it matters too much since you can set the Default GUI, but I do think it should be consistent.Why should it? Personally, I don't think that creating an unnamed GUI should make it default - other than the fact that there may be no other way to reference it (outside of finding the hwnd).
...why does adding a name need to make it not set default?
[concerning Gui, New] if this is the sole reason for it ...