<no net> and isolated copper islands

Layout
1

Hi there -

I don’t actually need a “ground” net, since I’m designing a simple adapter. I have an undefined instead. In theory, is there any difference in an isolated copper island that isn’t defined as “ground” and one that is? (…other than it will intelligently connect to grounded items from the schematic)…

2

If it’s isolated, then by definition it has no net.
A net implies that it’s connected to some other part of the circuit.