When you are writing an App. for a company or a person, what would you do when they start getting demanding when you are half way through something else for them? I don't just mean physical violence.

For instance tell them that it will up and ready soon. Then, when they click on the button or menu or whatever to start it up, it actually starts another program that says that they have contracted a virus from some porn site or something and that this virus will destroy their boot sector if they don't click on the button in 10 seconds. However when they try and move the mouse over the button it moves away from them. Then when the Counter hits Zero the App shuts the computer down.