wont they just keep the good ammy's and use some of their own gold to get a few cruddy one's to replace em?
the purpose is to get a high item level on the amulet for crafting
i.e to get +2 skills and 20 fcr on a amulet the ilvl needs to be 90
so to be 100% safe you need to gamble with a lvl 95+ character
but i've crafted a lot of good ones from lvl 94 character, it's just a 10% chance apparently for the item lvl to be 89 at that point.
so to be 100% sure u need lvl 95+ to gamble or a lvl 93 with terrorzone 95+ and pick amulets from there