In VW case, it was deliberate fraud to offset carbon emissions and pass emission testing and yet have a fun car that is easier to sell.
In the case of the Rigol, if anything at all it is a bug. It is the opposite of VW - even the software locks (a route to revenue) are not updated albeit they must be aware by now that their hardware is being upgraded for free. Do higher HW sales compensate for lower unlock sales? Perhaps. But even if it was a marketing decision to give out free features - it a far cry from fraud... Competitive yes - fraud no.
Open sourced software would be nice, but I find it hard to envision that anyone would build software that supports all the types of devices (e.g. the FPGAs and processors) and architectures needed for a real hardware scope. We all want the source code to fix the little bugs that irritate us. But the majority of the software is okay and proprietary to the manufacturers choice of hardware and software infrastructure (FPGA, Processor(s), Display, Analog Interfaces, etc.).
It is hard to do an open source embedded (Squeezebox is one exception that I can recall that worked - but started as a cooperation between the developers and the community - and also severely limited their ability to expand the system)... But open source without the manufacturer's help always ends belly up like the Open Sourced SamyGO (open sourced Samsung TV Firmware), like the Playstation hacks etc.
There are myriads of open sourced scopes for Android, PC, even Apple devices (at base audio frequencies). As for hardware open sourced scopes, Red Pitaya and Labnation both tried and ended up being half open sourced, half walled garden, with inadequate software, limited bandwidth and prices which at 2 channel 30MHz get them to within $150-200 of a base Rigol DS1Z. And using software buttons (ugh) so not a real hardware scope...