Personally I did try and brush it off. I was told by my manger that if it were to ever happen again close the window and get the manger. Even if it's not really meant and never would be carried out we'd have to take it seriously. Maybe, not calling the cops right away, but if it were to go to far, then we would call the cops. Though I've loved all your comments.

Also as taking death threats seriously, even if people really don't mean it, my younger sister in high school got into a pickle because of something like this. A group of her and her friends were writing death threat song lyrics that were implying to hurt and kill another student. the student's girlfriend called the cops and at 10:30 at night a cop showed up at our door and told her, even if she didn't mean it how serious it is. If you're reported making a threat to someone's life, if anything happens to that said person (can't remember for how long) the cops will always come to you and question you think you hurt them.