Re:Ask HN: Finding the Australian Aboriginal flag in all art...
by pbhjpbhj on Monday August 17, 2020 @01:07PM
(#24189206)
Authorship isn't sufficient for ownership of copyright.
Trademark is probably the issue that's most pertinent. Even if the flag weren't a work owned by Thomas, for copyright purposes, then it seems it's their trademark (registered or established by use).
IANAL
IANAL, but I believe you're 23 years too late