Your customers need access to your data - that is the service you provide that they're willing to pay you for. But what if you're on opposite sides of a river? You would build a bridge. How do you make sure it's safe? How do you make sure they can travel across the bridge with privacy in mind? What happens if there was an accident on the bridge? It's a simple metaphor you can use to explain the important of information security to business partners who are just thinking about the business, and why information security matters so much.