Each Ditto code is linked to a specific receiver. Many users can connect to that receiver as long as they have the Ditto code associated to that receiver. If you are on the road and visit an AirPlay/Cast receiver that is not registered to Ditto, you won't be able to connect via Ditto. An AirParrot license is linked to one computer and does not need to be registered to each individual receiver. AirParrot can connect to many Apple TVs, Chromecasts and Reflector-connected devices. AirParrot is what you should use in these instances.