Alexander Terekhov wrote:
Non-commercial use IS a common scope-of-use limitation
The patent holder limited the manufacturer to selling the
amplifiers to non-commercial users. When the manufacturer sold
them to commercial users, those users did not acquire the
patent-exhaustion rights the non-commercial buyers got.
The GPL licenses copying and distribution only if the work as a
whole is distributed as specified by the GPL. Otherwise there is
no legal right to do so, and doing it anyway is infringement on
the rights of the copyright holder.