In Australia, in 1924 Ernest Fisk (later Sir Ernest) of AWA - Amalgamated Wireless (Australasia) suggested the introduction of a sealed set system (also known as a sealed receiver) where radio sets could only receive the transmitting service (or services) to which they were licensed.
There appears to have been little attention at the time to a third possible model; that of the licensee charging for advertisements, as was done in the United States.
There were one or two A Class stations in each major market and these were paid for by a listener's licence fee imposed on all listeners-in.
A lot of today's electronic game products have chipsets with keys, that make it difficult or impossible to interchange the integrated circuits in the device, in order to repair it, or to carry out certain interface or applications.
Without effective circumvention, it is necessary to get Sonic Stage to produce a wave file, and to never overwrite your original minidisc, in order to adequately preserve whilst distributing your recording.