Marketing with fear is a powerful tool. Fear is a universal emotion, it's viral and people will go to great lengths to make it go away.
Some items can't be marketed without fear. Seat belts, for example. They're not convenient, good tasting, fun to use or profitable. Fear works great in this case.
An essential question to ask, though, is who benefits? In the case of seat belts, the use of fear directly benefits the prospect, because using seat belts not only decreases fear (peace of mind) but improves safety. It gets a little dicier if you're selling a placebo--increasing peace of mind without increasing safety (a $30 warranty at the cash register for a $16 item is not a smart financial investment, though it may help you sleep better.)
What if the marketer not only doesn't create peace of mind, but intentionally destroys it for his own benefit? Sometimes, fear is used as a marketing tactic even if it doesn't benefit the prospect at all. That's because news organizations like CNN and various organizations and politicians can benefit. Craig sends us this photo of a convenience store hoping that fear will sell some duct tape.
Without terror, you can't have terrorism.