It has been seen that many who plan on killing others will out themselves on social media. To ignore that is to be a modern day ostrich and hide your head in the sand, saying, “It isn’t so, it isn’t so.”
There is a noticeable difference between posting “they should be shot” and “I am going to shoot them”. In case you can’t tell the difference, one means that you think it is a punishable offense and the other says that you are going to take that into your own hands.
The trouble for me is they are both subjective 5 people can read someone's post and come away with 5 different feelings.
If someone says I'm going out and partying my ass off gonna do shots all night should we send the police to there home with a tow truck to remove all their vehicles?
Than there is context, do you have an inside joke with anyone that would give the total wrong impression if overheard by someone not in on it?
Lastly peoples online personalities often differ from their real life ones and while Keyboard warriors can be annoying its not a criminal offense.
I cannot speak to how often someone posts about a killing than actually goes out and does it but I don't personally get the impression its as common as its being portrayed.
My advice is to delete all social media such as Twitter and Facebook its simply not worth participating in.