Peter Drier’s neck surgery bills didn’t surprise him, even $133,000 from the anesthesiologist and $56,000 from his Manhattan hospital. But what was $117,000 from an “assistant surgeon”? Drier, a bank technology manager, had run into a growing US phenomenon known as “drive-by doctoring,” the New York Times reports. In such cases, consultants, assistants, and other hospital workers who are out-of-network providers will shock insurers or patients with formidable fees, often 20 to 40 times above the usual rates. “This has gotten really bad, and it’s wrong,” says a Louisiana insurance commissioner. But trying to change it means facing “a hornet’s nest of financial interests.” So why the big fees? Maybe it’s because Medicare and insurers have been paying surgeons and health care workers less money (neurosurgeons, for example, saw their average base salary fall from $630,000 in 2010 to $590,000 this year, according to a staffing firm). But such billing strategies—like calling the operation an “emergency” so a second surgeon can secure a separate payment—”raise serious questions,” says the Times. Insurers have sued over the fees or refused to work with surgeons who charge them, and a few states are offering legal protection against surprise bills. Meanwhile the Wall Street Journal offers tips to avoid them, like consulting with your insurer and doctor before receiving medical treatment. But “obviously, this isn’t always possible,” the Journal adds.