I'm not entirely clear on what the issue is. Our companions are our "pets", but they do allow us to tackle solo content which we wouldn't normally be able to. Needing on something for our "pet" actually improves our character, as an extension. The only thing I think should be changed, is to make all need rolls BOP, or only vendor for 1 credit as someone else suggested, so that anyone who NEEDS has little other incentive to NEED. Greed allows the sale, trade or auction of the item.
Having played WOW for a number of years Ive come to the conclusion that the only way you are not going to have loot drama is to ensure that only those that can use the loot can roll need on the loot, and even that doesn't remove all drama.
I say just play the game, and if someone wins something that you could have used, meh, an upgrade is right around the corner. Playing the game does not ENTITLE you to loot, and unless you agree on the loot rules in advance, like we used to do in WOW, that's no reason to blacklist someone. This blacklist just seems rather silly and childish to me, and I'm sorry if that offends.
Endgame would be a different story, but even there, you should be have loot rules explained well in advance. If someone jawas there they risk not being invited back to another chance at the endgame, which is a risk they will have to take.
so, by making it BOP, people who think their companion are an extension of themselves will need.. if ALL the other group members think otherwise, the item can't be traded anymore and thus cannot go to someone who actually needs it...
there is only 1 solution to this:
discuss it with each group you join, and when someone ninja's you report them in the chat.
Even in WoW you could get banned for ninja rolling, but apparantly nobody knew this XD