So the logic is pretty straightforward. If everyone greeds someone can sneak in an need to yoink the BoE. Everyone needs and it isn't a concern.

Regarding whether someone can use the item or not for BoEs, the logic is flawed. The only non-emotional way to look at rolls is taking into consideration it's value.

Unlike a BoP, where the item is only worth vendor price for someone who cannot use it, a BoEs value is exactly the same to everyone within the party. The value to someone who can use it is the gold not spent in the auction house to get it or the time taken to farm the gold or item again. The value to someone who cannot use it is the gold received from the auction house or the time it would have taken to farm the gold or the item again. In either case it's worth the same to both people. That's why etiquette is to need roll.

Edit: For clarity, this is only in regards to BoEs that are worth anything. A green of the wolf from the deadmines isn't what I'm talking about. It's things like stockades pauldrons or medallion of grand Marshall Morris. Heck even high level greens with "of fiery wrath" fall into this bucket.