So Diury if you have a girlfriend and your best friend needs one, you give him yours :)? Or you help him find one?
Sorry for the lack of manners of this example but it may help you with your lack of understanding of what a teamwork means. Playing with someone doesn't necessary involve giving access to everything you worked for.
By no means you should share your account or items. If you want to borrow some items, borrow the ones that are useless to you and not some important item, because it is really risky and we don't support it.
You can share drops, stones, upgrade items, you can even create a special character where to put all these stuffs so that if any of you needs can take them, but only because they are drops, if someone steals them is not the end of the world, but if someone steals all your items, is pretty much game over for you.
We never ever supported sharing, so I don't understand why are you asking us if we think about the players who share, the answer is obviously no.