A method performed by a target device for transferring of playback of a media content item from a source device to the target device, the method comprising: operating the target device in a primary mode associated with a first account associated with a user of the target device; responsive to receiving a guest mode signal while operating in the primary mode, causing the target device to begin the process of entering a guest mode, which includes: recording ambient noise of a media content item being played back at the source device to create an ambient noise recording that includes at least a portion of said media content item; sending, to a media identification engine of a media-delivery system, an association request for associating the target device with credentials of a second account associated with a user of the source device, the association request including said ambient noise recording for identification by the media identification engine; responsive thereto receiving, from an access management engine of the media-delivery system, credentials wherein the credentials have been obtained by the access management engine from said second account having been identified as having caused the playback of a media content item associated with the ambient noise recording; and operating the target device in the guest mode associated with said second account, which includes: sending a playback request to a media server application of the media-delivery system using the received credentials; and responsive thereto receiving a media content item from the media server application for playback in the guest mode. operating the target device in a primary mode associated with a first account associated with a user of the target device; responsive to receiving a guest mode signal while operating in the primary mode, causing the target device to begin the process of entering a guest mode, which includes: recording ambient noise of a media content item being played back at the source device to create an ambient noise recording that includes at least a portion of said media content item; sending, to a media identification engine of a media-delivery system, an association request for associating the target device with credentials of a second account associated with a user of the source device, the association request including said ambient noise recording for identification by the media identification engine; responsive thereto receiving, from an access management engine of the media-delivery system, credentials wherein the credentials have been obtained by the access management engine from said second account having been identified as having caused the playback of a media content item associated with the ambient noise recording; and recording ambient noise of a media content item being played back at the source device to create an ambient noise recording that includes at least a portion of said media content item; sending, to a media identification engine of a media-delivery system, an association request for associating the target device with credentials of a second account associated with a user of the source device, the association request including said ambient noise recording for identification by the media identification engine; responsive thereto receiving, from an access management engine of the media-delivery system, credentials wherein the credentials have been obtained by the access management engine from said second account having been identified as having caused the playback of a media content item associated with the ambient noise recording; and operating the target device in the guest mode associated with said second account, which includes: sending a playback request to a media server application of the media-delivery system using the received credentials; and responsive thereto receiving a media content item from the media server application for playback in the guest mode. sending a playback request to a media server application of the media-delivery system using the received credentials; and responsive thereto receiving a media content item from the media server application for playback in the guest mode.