Douglas Merrill’s sister-in-law Vicki needed new snow tires. Without them, the single mother of three, who was going to school while also working full-time, couldn’t get to work. She’d lose her job.

But Vicki was in a bind. She couldn’t pull the money together to cover the unexpected expense. So she called Merrill, who gave her his credit card number. As the former chief information officer at Google, he could afford to foot the bill. But he was curious: What would Vicki have done if she didn’t have a well-off family member to turn to?