HDMI 'keys' were a thing a while ago, especially in set top boxes. They effectively stopped people putting cheapy boxes in front of splitters / switches etc. I haven't heard about issues with this for a few years though... maybe they have now finally specified a number of HDMI chipsets so that everyone knows the hard limit? Previously it was up to the manufacturer to specify the number of keys it would allow...
This industry is not getting cheaper and cheaper, we're simply convincing ourselves that we have to push the cheapest option to customers. #makesonosgreatagain
