Sean Yox, a songwriter who spends time each evening at a Pret a Manger cafe near Union Square in New York, often leaves his laptop on the counter when he goes to the bathroom. Yox does not sit with a friend or family member who can watch his computer. Instead, he trusts the very strangers he might be suspicious of."You see who's coming in and coming out, what type of people are coming in and out," he said. The people tend to be "more serious," he said, so he takes his calculated risk. Especially if taking his belongings to the bathroom means losing his seat.In an age of heightened security at airports and passwords guarding everything from email accounts to Twitter handles, some strangers continue to place and justify their trust in one another. Every day, people across the United States leave valuable belongings -- such as laptop computers and smartphones -- unattended, or watched only by a stranger, in public places like cafes.Keith Weigelt, the Marks-Darivoff Family Professor in Wharton's management department at the University of Pennsylvania -- and co-author of the 2004 study "Trust Building Among Strangers" -- said that about 10 to 15 percent of the population is "predisposed to trust in people.""It's not like they're irrational," Weigelt said. "They just view the world slightly different."Part of that worldview depends on where in the world they live."Midwestern people seem to be more trusting than people on the East Coast in major cities," said Weigelt, who is from the Midwest. And the higher the value of a person's belongings, the less trusting the person will be, Weigelt said.Jay Sauer, a barista at Meadowlark Coffee and Espresso in Lincoln, Neb., has seen people leave laptops, purses and cellphones unattended. Usually, customers leave their belongings for just a few minutes, while they use the bathroom, take a smoking break or go to the grocery store next door, Sauer said. Customers will ask him to watch their things "maybe twice a week.""We have a lot of regulars," Sauer said. "They're pretty comfortable."At the Otherlands Coffee Bar in Memphis, barista Ben Bauermeister said customers will ask him to watch belongings once in a while, but leave their valuables unattended for short periods "dozens of times" each day. He also cites the comfort factor."Most people feel pretty comfortable," he said.It isn't just a matter of blind trust. People who trust strangers with their belongings factor into their decistion distance they will be straying from their items, time they will be gone, and the type of people in the area.Yox trusts the crowd at Pret a Manger but would not leave valuables unattended in a mall, he said, because "you can't control people streaming" there. When Pret a Manger is crowded, he will ask a stranger to watch his laptop or will take it with him. Yox does not like to pack up his computer because he would need to log back on when he was ready to use it again. "It's complicated," he said.Matthew Buccambuso, a barista at Java Jungle in Reno, Nev., will watch customers' belongings when asked to do so."It's pretty easy to keep an eye on something while you're making drinks or at the register," he said.Not everyone is so trusting. Grace McKinnon, an opera singer who was sitting at a table at a Manhattan Starbucks, said that she never left her valuables unattended. She will leave her books, but not her phone or purse. She has watched other people's belongings for them, however."People ask me to do it all the time," McKinnon said.Even if she were not asked to watch a stranger's laptop, if someone tried to steal it, "I think I'd say something," McKinnon said.Robert Danforth, a writer sitting in a Manhattan McDonald's, said he would watch items if people asked him to. But if they didn't ask, he doubted he would pay much attention."Maybe peripherally," he said. "I'm not vigilant like that."