A few weeks ago, I came out of the grocery store on a hot sunny afternoon and stopped short. Two young kids, sisters it seemed, were sitting in the backseat of the car next to mine. The windows of the car were rolled up, the car was turned off, and no one was at the wheel.

I immediately did some quick math. I’d been in the store for just a few minutes, so I knew the kids hadn’t been there long. The girls, who looked to be about 12 and 9, didn’t look uncomfortable, though it was pretty hot out. But when I got into my own car, the air was stifling, and I thought I ought to at least wait to leave until I confirmed that the girls were OK.

Already I felt conflicted about my response. In general, I worry that my own children/kids these days are overprotected in the name of safety. And since the day a random old lady scolded me for not putting a hat on our infant daughter, I’ve strived not to be one of those busybodies telling other people they’re parenting wrong. Sure, I judge—I’m human!—but I try to keep those judgments to myself.

But there was still something jarring about seeing two kids alone in a car on a hot day. I remembered my one brush with heatstroke, when I didn’t realize how sick I was until I almost passed out in the middle of a Mexican market. A similar lack of recognition on the part of these girls could be fatal, as it is 15-25 times per year in America, and I’d be the passerby who did nothing.

I could think of plenty of reasons not to intervene, though. I didn’t have my kids with me, so I could easily see any overture being interpreted as a creep move. An adult man, alone, trying to coax two girls out of their car—that could end badly for me. The girls seemed old enough to help each other and to get out of the car if they got uncomfortable. And indeed, though I’ve never left my kids in the grocery store parking lot, I have left my older daughter, who is 9, in the car for a few minutes as I ran into school to get my younger one. If I walked out and found some meddler trying to tell my daughter her health was in danger, I’d be pissed.

Still, it was hot. A woman climbed into her car on the other side of the kids, and I asked her if she thought we should do something. “They seem old enough,” she said, and drove away. But I still waited. The older girl fanned the younger one. They were both sweating. Ten minutes had gone by, and across the street, the bank’s time-and-temperature sign read 88 degrees.

So, what would you do?

On a recent episode of Slate’s parenting podcast Mom and Dad Are Fighting, I posed this question to my co-host, Allison Benedikt. She suggested she might stick around to make sure the kids were OK, but would not confront the parent in question when he or she inevitably returned. She also asserted that my solution to the problem in the moment was not good enough: I bought a huge bottle of water, got the kids’ attention, left it on their trunk, and drove away—sighing with relief when I saw an adult woman walk up to the car seconds later, pick up the water bottle with a What the hell? expression, and get in.

We got more listener email about that segment than any we’ve done, and the feedback was almost unanimous: Why didn’t I call the police? More damningly, why wasn’t calling the police even an option I considered? And it’s true: Though I half-mulled calling 911 that day, I didn’t mention it on the show, for fear of being, you know, That Dad.

In our next episode, we explored both sides of that question: Why calling the police might be the right thing to do, and why it might be sentencing a fit parent to a yearslong legal ordeal. We invited Tabitha Kelly, bureau chief of my county’s Department of Child and Family Services, to tell me what I ought to have done. She was blunt: “Bottom line, Dan, my recommendation is that if you ever see a child left unattended in a vehicle, call 911 immediately.”

Which is certainly the advice you would expect someone from a child protection agency to give: Let authorities and experts make the judgment calls—don’t make them on an ad hoc basis yourself. Weigh that advice, however, against the fate that befell Kim Brooks, a mother who wrote a thoughtful and chilling essay for Salon about being charged with contributing to the delinquency of a minor when she left her 4-year-old in the car for five minutes on a cool day to quickly run an errand. (A passerby took a cellphone photo and called the police.)

Now, thousands of dollars of legal bills later (and a sentence of 100 hours of community service), she’s not so convinced she did anything wrong—and she’s supported in this belief by the author Lenore Skenazy and her “free range kids” philosophy. The Free Range Kids website, dedicated to “fighting the belief that our children are in constant danger from creeps, kidnapping, germs, grades, flashers, frustration, failure, baby snatchers, bugs, bullies, men, sleepovers and/or the perils of a non-organic grape,” is rife with horror stories of parents being confronted by police for, say, letting their kids play in the woods.

Surely there’s got to be a middle ground between doing nothing for kids who might be in danger and dropping a dime, as the “good Samaritan” in Brooks’ case did, on a parent whose kid was, in fact, totally fine. Perhaps the solution requires not being too chicken to confront parents (in a courteous way), and, when a situation becomes dangerous, to swiftly and confidently call the police.

But what is dangerous? A baby locked in a hot car demands immediate action. But beyond that obvious case, the actual danger that children are in during pretty much any scenario is pretty low. Those girls I saw in that car were more likely to suffer a heart attack than they were to be abducted by a stranger; they were dramatically more likely to be injured on the drive home than they were in the parking lot. (As for somehow causing the car to move—maybe that’s a problem for stick-shift cars on the hilly streets of San Francisco, but in most flat parking lots, that’s not an issue.)

In the parking lot that day, I was fearful that those kids were in danger, but they weren’t, at least not yet. Sticking around for a while to keep an eye on them was an OK move on my part. Sticking around even longer to make sure they were not in danger would have been a better one. A quiet conversation with the mom when she appeared might or might not have been helpful; it surely would have annoyed her, but might have reminded her of the optics of her choice (and that next time, the observer might indeed call the cops). But it’s hard to envision a scenario in which me calling the police would have accomplished anything positive.

I can say this, of course, because the mom came back. Had I waited 15 more minutes and no grown-up appeared—what should I have done then? It’s difficult to delineate on the fly between a situation in which a child is actually in peril and one that simply makes me uncomfortable. But I can’t, as a rule, agree with the many listeners who told me that the only right move is to call the cops. Do you?

Listen to more episodes of Mom and Dad Are Fighting, in which Dan and Allison debate raising kids in the city versus suburbs, get advice on how to talk to college-bound kids about campus sexual assault, and discuss the stigma of having, and being, an only child, plus reveal all of their parenting triumphs and fails.