The way I understand it is - 10 min before a game not involving ULL - they are going to take an estimate of how many seats aren't being used. They will sell general admission seats for that estimate. So if they think there aren't 500 seats being used - they will sell 500 GA tickets. You can go sit in an open seat but if the person that has the "real" ticket for the seat shows up - you have to get up and find somewhere else to stand.