shuffleAtEventStart

If enabled, users in the prequeue will be shuffled randomly at the event_start_time. Requires that prequeue_start_time is not null. This is useful for situations when many users will join the event prequeue at the same time and you want to shuffle them to ensure fairness. Naturally, it makes the most sense to enable this feature when the queueing_method during the event respects ordering such as fifo, or else the shuffling may be unnecessary.