I replied to this topic in the ideas forum, but as i mentioned, i feel it is closer to a bug that really needs fixing/addressing - there is too much potential for mistake/deceit/drama not to fix this issue.
the issue is that "used" multi-use items (powders, essences, tools, even RKs) can sold fraudulently or mistakenly as "brand new" in players' SDBs.
to give props/credit to Disturbed for bringing it up to start with, i am linking to his post here as he inspired my post here:
http://www.glitch.com/forum/ideas/24874/