need 'em if you need 'em.
it's certainly not "a ninja" as a previous guy posted.. if you somehow swapped it to master loot, and took it, sure that's "a ninja." each player has the opportunity to roll. if you greed because you "though everyone would" then you're a fool for passing on something you needed.. and if you didn't need it, then why would you be upset if someone else did?
no. bca should be greeded by all. pretty much everyone can use them for something - if someone really needs they can either ask up front (as pretty much every normal person will assume you'll greed otherwise) or buy one off the GTN afterwards if they greed and don't win.
if anyone ever asked for it up front i'd happily pass. Needing is something a 12 year old would do.