I remember there was a shareware x86 assembler called A86 back in the 90s. It was easier to use than Microsoft's. In the documentation, it said it would encode

I remember there was a shareware x86 assembler called A86 back in the 90s. It was easier to use than Microsoft's. In the documentation, it said it would encode a fingerprint in the output opcodes so they could go after anyone using it for commercial purposes without a license. This would be possible (according to them) because there are instructions that could be encoded in multiple ways without affecting the operation of the code. I wonder now if they actually bothered, or if it was just there in the docs to make cheapskates think twice.