Mike Blake / Reuters

The Zipcar door would not open. My brother and then my sister held the card over the reader and waited for it to unlock. I held the card over the reader and tried to do the same. The baby fussed. The ocean crashed. The sun burned through the fog. Nothing happened.

Here is the Public Service Announcement part of the story: If you take a vehicle loaned out by Zipcar—a rental service where drivers use RFID cards or a mobile app to open up the car—to an area without cell reception, there’s a chance the car will not work. The doors won’t open, and even if they do, the engine will not start. And because you will be in an area with no cell reception, it might be impossible for you to call for help.

It is a particularly vexing part of the give-and-take of attaching everything to everything. With services like Zipcar, your rental car becomes not just a car, but a node in a complex, connected system. The same is true for your Uber ride, or your cup of coffee made by a Wi-Fi–connected machine, or your Peloton workout. All this connection means easier access, faster service, cheaper prices, better features. But it also means that things can go very wrong.

Sometimes that means you don’t get your cup of coffee, or you need to call a cab the old-fashioned way. Sometimes it means you are stranded in the middle of nowhere, a fussy baby in one hand and a useless cellphone in the other. It means a multiday extraction operation requiring a flatbed tow truck. It means turning your weekend of hiking and forest-bathing into a logistical nightmare.

Not too nightmarish of a nightmare, thankfully. I had gone to a remote part of the California coast with my brother, sister, husband, and baby, with our car and a Zipcar. One morning, after waving the card over the reader what felt like a thousand times, we realized the thing was no longer working. We used a landline to call Zipcar, whose representatives told us about the reception issue. We could abandon the car, they said, and they would waive the normal fee. (Thanks!) Or we could wait for a tow. Unable to get a cab to come to us, we waited. A tow truck took us to a lot with reception, where the rental failed to start. We needed another tow to a town where we at last abandoned the Zipcar and made our way home.

It all worked out fine. But it might not have. I shudder to think about limping back to a trailhead with no more water in my backpack, only to find a car that would not start. Or getting locked out and marooned in Death Valley, perhaps with medicine trapped in the car.

The “out-of-comms scenario when a member is unable to access a vehicle is extremely rare,” Jeff Prus, Zipcar’s vice president of product and experience, told me in an interview. But it does occur. Zipcars in general work just fine when they do not have cell service, he said, as they have some internal memory that lets them function even when out of touch with the company servers. Indeed, making sure that the cars work when out of reception is a “mission-critical success factor” for the company, he said. Still, cars without reception become vulnerable in a few scenarios: when members lose or do not have their physical Zipcard with them, when they exceed their reservation time or want to extend their Zipcar reservation, or when the vehicle battery dies. That last scenario was the one my family and I found ourselves in, though we did not know it at the time.

Such issues might be rare—Prus declined to give any hard numbers to quantify how rare—but online, tales of the dreaded “out-of-comms scenario” abound. Zipcars abandoned for days; Zipcars stuck in the woods; Zipcars stuck on the seashore; Zipcars stuck in garages; Zipcar users resorting to hitchhiking.  

Tess Rinearson had finished a 17-mile hike to the top of Mount Tamalpais with her boyfriend and some friends, only to return to a Zipcar that would not start. “We were super wiped,” the Bay Area technologist told me. “We tried tethering. We tried walking to get service. We realized it’s not us who need service. It’s the car that needs service.” They ended up using the Wi-Fi at a fire station while Zipcar sent them a tow truck from the East Bay. “We actually got really into figuring out what was going on,” she said. “Everyone on this hike was a programmer. We were like: How is this failing?”

A similar thing happened to Tom Coates, another Californian and, as luck would have it, an expert in the internet of things. He used a Zipcar to get to the Getty Villa, part of the J. Paul Getty Museum in Los Angeles. His mistake was to park in a garage, where his bars went to zero and he found himself stranded as the sun went down and the museum closed and the on-staff security guards started to circle in annoyance.

“The entertaining element was that I was stuck in this bizarre environment with nobody there,” he told me, describing the faux-Mediterranean estate and its priceless works of art. “All I really had was Twitter for company, so I’m there narrativizing the thing, writing jokes. I had friends all around the world being like, ‘I’m really enjoying your thread about being trapped in a museum!’”

The not-entertaining element involved making what he half-jokingly estimated were “17 calls to Zipcar” figuring out how to get a tow truck on the museum grounds, staying warm, and placating the security staff. “I’m very aware of how this stuff works,” he told me. “I was amazed by this one.”

He was amazed—and I was amazed—in part because Zipcar does not warn users that they need to take extra precautions in areas without reception, whether the bowels of parking garages or overlook points on mountainous roads. The Zipcar website does mention that you might need to hold your Zipcard over the scanner for a few extra seconds in garages, and that you should make sure you have reception if you plan on using the mobile app to open a car. But that is it.

Prus said that Zipcar does try to remind users “at just about every touch point” to keep their physical Zipcard with them, which solves many users’ issues in areas without reception. The system works almost all of the time, he stressed.

Unless it does not. The internet of things makes life so easy: Hold a card over the reader and pick up your rental car, swipe on an app and find a date, ping a car to pick you up wherever you are. But the problem with using services dependent on a network is that you are then dependent on the network. And on yourself to figure it out.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.