1. A computer system, comprising: one or more hardware processors; one or more communications devices; and one or more computer-readable media, at least one of the one or more computer-readable media having stored thereon computer-executable instructions that, when executed at the one or more hardware processors, cause the computer system to perform at least the following: receive, over the one or more communications channels and from a first user device, a first user identifier of a first user and a tracking code that is physically imprinted on an article; obtain one or more stored data records from the one or more computer-readable media, at least one of the one or more data records relevant to custody of the tracking code; determine, from the one or more data records, if the first user identifier is permitted to take custody of the tracking code and, based on the determination perform the following: when the first user identifier is not permitted to take custody of the tracking code, send, over the one or more communications devices, one or more first messages to the first user device indicating that the first user identifier is denied custody of the article; or when the first user identifier is permitted to take custody of the tracking code, perform at least the following: determine, from the one or more data records, that custody of the tracking code is already assigned to a second user identifier; update the one or more data records to assign custody of the tracking code to the first user identifier; and send, over the one or more communications devices, one or more third messages to a second user device indicating that custody of the tracking code has been reassigned to the first user, and which causes a second display at the second user device to indicate that custody of the article onto which the tracking code has been imprinted has been reassigned to the first user.