The customers enforce this. IANAL, but afaik there's no law (in the US) that enforces this. The only place I know of that may have a relevant law to enforce th

The customers enforce this. IANAL, but afaik there's no law (in the US) that enforces this. The only place I know of that may have a relevant law to enforce this is Norway and their Norwegian Marketing Control Act that prohibits withdrawing a key feature after sale. Accidental upgrade after a repair under warranty may or may not be included in this.