Mike,
Maybe some people closer to the tournament may know the story better.
I don't know how people were selected to be part of this "tournament" or last "tournament" they held.

You are correct when you say "A tournament does not have to be publicly advertised! I have been invited to and played in many tournaments there were NOT open to the public."

Some big players that love tournaments may take offense that they were not invited to join.

In the casino biz managers hate to get complaints - and the people who do complain - will get what it takes to make them happy.
All is speculation - except the last statement,
Pete