nstead, the number of reporters required to vote on an event scales with the volume traded in the event's market. More volume traded = more reports needed. Specific reporters are assigned to events at random, weighted by their Rep holdings. For details, please see Joey's in-depth blog post on scaling Augur.
Understand it, but... An example. We have 2000 rep holders and 10mln events to reporting period. If we take 100 report per 1 holders, we will have 40 holders per 1 events, with different amount of rep. So it will be very centralization and unreliably. Also if it will be not high liquid market, so reporters be a less then 40 per one events?
What if market itself will decide the result of events? If event for a long time traded on liquid market with the odds close to 100%, this market outcome may be determined without the participation of reporters with same 100% accuracy. Because It will be infinitely costly bet against events, whose outcome is already known
I will try to read blog post, but not native language