You’re getting downvoted a bunch here, but I believe your basic point is valid. To take it back to the GP: SGID bit and other such OS and/or filesystem specific

You’re getting downvoted a bunch here, but I believe your basic point is valid. To take it back to the GP: SGID bit and other such OS and/or filesystem specific semantics are not the best measurement of someone’s overall UNIX understanding. Now, IMO asking someone if they understand what the difference is between chmod <octal notation> VS chmod <friendly notation> is and why it exists is a bit more telling, because this touches down on what interface most unix filesystems try to present and also how they’re implemented to a degree. The specifics on any given system are just a manpage away but the general understanding only really comes from having absorbed some actual unix interactions. And certainly knowing more than just Linux should get one bonus points...