> Take a sentence as volatile as "I'm going to kill you." Standalone, I’m calling 9-1-1.

Had to do that once, pre-emoji. I have a domain in .com which is also a domain in .co.uk. That's owned by one of the famous British "public" (i.e. private boarding) schools. I used to have a catchall email address for that domain, and once in a while I'd get student emails, which I'd return with a note about why the right TLD matters.

One day, I got a student-to-student email "I am going to kill you tonight." No indication of humor. This was shortly after the Columbine massacre. I couldn't ignore it.

I'm in California, and the message was from the UK, where it was late at night. I had some trouble getting the right phone number, but after a while I was on the phone with the very British headmistress of the school, who'd clearly been awakened for this. Once I read her the message, she was thoroughly annoyed, but not at me. She recognized the student's name. It was made clear that someone was going to have a Very Bad Day. "He's only 12", she said.

If that message had come from a US school, there probably would have been a SWAT callout.

Presumably you could’ve just forwarded the email to the intended recipient.