A sharp stomach pain in the middle of the night. A knee bent the wrong way on the soccer field. A blinding headache out of nowhere in the middle of the workday. An ambulance ride to the nearest emergency room. It’s in times like these that Americans and their families are most vulnerable – and most vulnerable to surprise medical bills.

When patients experience health emergencies, they shouldn’t have to worry if the doctor they’re seeing at their in-network hospital is actually out-of-network and that they’ll be charged an exorbitant bill for care when they had no choice of treatment. Unfortunately, an unexpected trip to the ER often tops the list of scenarios that will likely lead to a surprise medical bill.

Not all hospitals or providers are responsible for surprise billing. It’s likely not your family physician, or your kids’ pediatrician. But those who are responsible have an outsize role in the egregious trend and are often driven by profit more than patient care. The New York Times spotlights one of the most effective, and harmful, money-making strategies that certain providers have used to take advantage of the loophole around emergency care.

Here’s how it works.

American patients go to great lengths to make educated decisions and look for opportunities to lower their health care costs. But there will always be some situations where patients do not have time or access to enough information to make an informed choice about their care. When families need an ambulance for a loved one, the last thing on their mind is taking precious moments to confirm the ambulance is in-network with their health insurance. And that’s the way it should be – Americans should be able to care about their families first, without worrying about surprise medical bills later.

Once patients get to the ER, they still aren’t safe from surprise medical bills – because odds are they’ll be treated by doctors who do not actually work for the hospital, but are instead employed by one of the many physician-staffing companies that hospitals now contract with. These groups, funded by private equity investors who profit from out-of-control health care costs, are increasingly pushing to keep their employees out-of-network with most insurance companies.

Most egregiously, patients and their families would have no indication they were being treated by a contractor who is out-of-network until they got home to find they’ve been stuck with an exorbitant surprise bill. While patients are recovering from health scares and families are trying to figure out how they can afford to pay for the excessive surprise medical bill, that private equity firm is on the other side waiting for their windfall.

It’s not just unfair, it’s infuriating.

Out-of-network providers should not be allowed to exploit this loophole in the system at the expense of patients seeking immediate care.

As we work to end surprise medical billing and pass meaningful reform that protects patients, families, employers and taxpayers, we can’t lose sight of who is quietly driving the problem in the first place – and benefiting from American families’ financial burdens.