I agree with Alhanelem. The 30-second delay is to allow for eventual-consistency to take place between the client and the server.
As an anecdote, I once logged in, dropped some Rabbit hides and d/c'ed ...all within about 20 seconds. I log back in to find that the rabbit hides are still in my inventory. So clearly, the synchronization between client and server still needs this delay.
It would be interesting to hear from SE though ...but who knows? I'd rather they add more content to be honest.