Hmm, this is the way I see it:
People that have the information have the right to keep it to themselves. However, they should understand that that information isn't going to be kept private forever - like Spirit said, it won't be a secret anymore if it starts to be spread around. Knowledge of where the item is and which monsters to get it from may be kept by the person who know's it - acknowledge and respect their privacy. So what if people don't want to tell everyone what they know? It's common courtesy to stop bugging them. If they want to share, they'll share it. Sooner or later, it will become known.
Secondly, I do not think there will be people farming for these items. People are people. Is the time spent on acquiring these "blue" pixels really worth it? For me, I say no. As AngellicDiety said, it's called "rare" for a reason. When you're hunting bosses or have CS items, you just get more chances of finding a "rare" item. You still need to accept the fact that it is still "rare", meaning that you might not get it. Otherwise, every tenth shop would have that item.
As for bots, I think that they might potentially become a problem. They're mostly not player controlled, so they could continue on for days just killing the same monsters until they get a drop. I don't often see a lot of bots though =/ and still, it's a "rare" item, so the chances of getting a blue item should be slim.
That's my input on this.