It may not be the first thing you want to hear upon checking into a hotel on vacation, but Homeland Security would like you to keep an eye out for terrorists, please. The agency has begun running 15-second spots on hotel TVs across the US asking guests to report any suspicious activity they see at airports or elsewhere on their travels, reports USA Today. It's like the modern duck-and-cover message: "Maybe you see something suspicious," says the ad. "Can you be sure? If you see something, say something to authorities."