OK guys just don't do this.
http://www.tsa.gov/press/happenings/belt_knife.shtm
That's not our knife but it would certainly be along the same lines as far as the law goes. Although the knife is not illegal. If you are using it some bad way the law is going to figure out how to prosecute you for it.
Hey a baseball bat is not illegal but if you thump someone on the head with it then the judge will look differently upon it.