What portion of the total registered market participants are chosen to judge a given claim?
There’s no reason it couldn’t be 100%, but the higher the percentage, the bigger the individual judging burden becomes. Assuming a minimum threshold for diversity of opinion, it would be better to keep the number as low as possible, and allow each claim to be more carefully considered. Also, the higher the percentage, the more likely a tragedy of the commons, wherein individuals compete to the point of dysfunction over the amount of total influence they hold. In other words, if you know you only have a 10% chance of being chosen, it might not be worth skipping dinner and other healthy activities on the off chance you could be called to duty.