How do you plan to handle security related dangerous items? For example, an user may ask you to deliver a package taken from one place to another place and you may arrange that but that package may contain dangerous/destructive/harmful materials which may be against law of the land where you operate.
You can ask user to confirm contents but he/she may lie and faithfully you may try to deliver and in between you may get struck in legal issues. If the origin is well known or reputed enough, then risk may be less but otherwise, there is an element of risk. Have you considered it? and how do you plan to handle it safely? Thanks.