I see your point Nick. I also don't think it was discussed specifically at the Summit, but I might be wrong.
When a player is all-in, I think if the action checks around on the river, or there is a bet and a call on the river, it does make sense to me to show only the hands eligible for the side pot first and work your way to the main pot. I think we explored this in a thread, and many of us agreed that while everyone does have to show in an all-in situation, it doesn't necessarily have to be all at the same time and before any of the pots are awarded.
I admit though that some may find it easier to enforce the rule if everyone just simply showed before determining the winners of any pots, particularly if the dealer does not have firm control over the table and there is a chance that the player contesting the main pot may refuse to show or walk away from the table. Under the "new" procedure, you could have the dealer focus on the side pot hand first and ignore the hands eligible for the main pot at the outset, despite having all cards turned up.
I could go either way - I was a bit surprised that an addendum was necessary for this particular issue. I would have preferred to keep this somewhat open and not have an addendum that specifically discussed it - it is more about preferred procedure than anything.
K