I think even the best standards can have ambiguities. SHOULD, MAY, etc. Assuming you're not running a Mac (where the vendor controls the entire stack), you've

I think even the best standards can have ambiguities. SHOULD, MAY, etc. Assuming you're not running a Mac (where the vendor controls the entire stack), you've got your OS vendor, your MB vendor, your every-single-external-device-vendor... ... and the interactions of all this hardware mediated through the OS, its drivers, and the reading comprehension and the development pressures of every single dev who's worked on any part of this stack. There's an awful lot of room for ambiguities there. Protocol definition at this level is kind of a collaborative lurching towards consensus.