Combat Zone is obviously different. It was introduced as though it were a real settlement and then it just wasn't for whatever reason
and what if someone just finds it normally?
I only heard about it from a diamond city guard, and if I remember correctly he was actually telling me to avoid it, which doesn't help
considering there was a bigass sign out front that said "NO STARTING FIGHTS", with another one inside and a couple dudes tied up and on display for rulebreaking, i assumed that if i didnt start anything the NPCs wouldn't either
it's not implausible that someone would aggro the guys outside before seeing a sign
the only reasonable way to indicate that they're friendly would be for them to look noticeably different, like zombiloin said