I think at that point your laptop is the least of your concerns. I don't let people get that close.

As a side note, Emerson Knives makes a really nice highly durable set of pocket knives with a "wave" that forces the knife open when you extract it from your pocket. It's many times faster than a switch-blade but legal in most states and durable enough blade and handle to pry anything apart. Check with the laws in your state.