1. Some user gives items to the bot for free, giving them away.
2. Some other user notices that the bot has items in it's backpack and "buys" them (like every other banking).
3. That other user gets the items for free.

That's because all of the metal that is being stored in such bot is used for future item/site refunds or for other situations which is urgently needed.

That's because the items which have been incinerated have quickly been grabbed by other users. Staff does not put items in the incinerator bot by request.