Actually, they have always told us in the past if you dont arrive at the entrance 1/2 hour before show time, you may get standing room only. We almost saw this happen last summer.
We arrived and gave our vouchers just about 1/2 hour in advance...maybe 32-33 minutes. As we walked up the walkway, people who showed up after us(probably at exactly 1/2 hour) were following us up. By the time we got to the top the regular line was being merged with the FDP line so people who didnt have the package were being seated in the Package Section. We were in one of the last rows before the handicap accessible rows. People sat in those rows. A few minutes later a CM came over and started yelling at them to get up,they had to move. They refused saying they did the package. And other people who didnt do the package were taking up their seats. One woman went and spoke to someone who looked to be a bit higher up than the CM who was yelling at them to get up. In the end everyone stayed in those seats and saw the show, but after witnessing that, I wouldnt cut it too close again.
I should add there was no one there who needed the handicap rows, the CM just wanted them to move.