I often have my own events in Casinos, Players when they play in that casino they have to adhere to both our Tournament Rules & Conduct and also the House's rules of conduct and etiquette, both tie up nicely now as Genting Casinos also comply with the TDA. If the casino decides to eject a player, and I am satisfied they will not get back in I will remove the chips from play and eliminate the player, it looks like from your post that there is a uncertainty as to the racetrack staff allowing the player back in, so I would likely leave the chips in play also in your situation, until you confirm with racetrack security the status of that player.
This is the extract of our Tournament Rules regarding the subject:
64 Player Leaving – Where a player leaves the TD shall remove their chips if they are satisfied they are not returning. Where there is uncertainty they shall remain in play, A player will not receive position of elimination if they do not return before two active players are remaining in the tournament.
Because it's the Racetracks ground you are in a near identical situation to me, you must observe their conduct rules and abide by them. I see no justification for a player getting his entry refunded because he has been ejected by a third party, I certainly would not refund a player ejected by the casino's security staff, if they had a heart attack or something which was ultimately outside of their immediate control, then yes I may well consider a refund or partial refund.
Remember a player can still be whisked away in an ambulance or be arrested and still make it back in time to continue play.
Regards
Stuart