If someone is needing on things that they don't need, warn them that will be kicked if they do it again. That generally fixes the problem. Needing for companions is not an excuse. Don't be afraid to start a vote to kick them out if they persist because it's what's best for the group, and hopefully the player will learn from his/her mistakes.
This is actually not the case in many of the groups with the introduction of F2P, yes this was not a problem before atleast not for me anyway. Nowdays it is very common that players takes items that they can not use. I am sure that most of them have been told before and know exactly what they are doing. In most cases they wait until all press greed/pass and then press need so it is a appearent ninja of the item. That is when I either try to kick the player or leave, in most cases I leave and start over without spending more energy on that specific group.
Bioware should make it impossible to need items that is not for your class like many other MMOs has already done.