I recently received a "cease and desist" from a company who competes with the company I work for with some subtle insinuations (without saying I personally would be in legal trouble... they imply it). It was sent to me via LinkedIn of all places. The company I work for has a valid mailing address that is easily googled, same thing with contact email address, phone numbers, etc. I suspect because I'm involved in web development they think I'll just take down the content they do not like / disable some things at their direction.
I ignored it, I had my employer contact them and respond as it's their deal. The issue the other company has is entirely BS. I am not a lawyer but I ran it by some lawyer friends who thought it was hilarious how misguided it was.
It seems like there should be some potential consequence to prevent threats that are that far off.