It should be up to the individual casinos and their opinions. There can never be a legal ban because he's not found guilty of any wrong doing, but in the court of public opinions he's completely guilty. If Aria feels that they don't want him in their casino they can ban him. I bet they hesitate to do it because Howard still has a number of high profile poker friends. If they ban him, none of those friends are going to come play in their poker room either.