Changes of date and/or time are permitted up to 48 hours, NO REFUNDS. If you are late due to weather or other reason site says they will do best to accommodate and gates close at 9:30. There didn't seem to be a strict crowd limitation, it just got more dense the later it got.
Having gone tonight in the rain, the answer is they will close, give you no notice or indication until you speak to a security guard. They 'offer' the ability to go back another night but it is the week before Halloween and no one is available to reschedule.
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