I'd like to point out that any time you have a chance of getting something -- no matter how slim the chance -- there will be players who grind until they have the maximum available amount of them. Everquest learned this lesson by creating ever-more-long-and-painful quests designed to make items 'rare', with the result that millions of college kids stayed up 48 hours straight waiting for a quest mob to spawn so they could pounce it and get the quest element that would eventually get them the item.