Image by Marco Verch

French law enforcement are warning about a troubling trend: People buying and selling forged COVID-19 test results so that they could be cleared for travel.

The cops arrested seven people last week for selling certificates to travelers at Paris' Charles de Gaulle airport that claimed to certify that they were coronavirus-free, The Associated Press reports.

It's not clear how many of the certificates, which cost between $180 and $360, they sold. But regardless of whether this was a large operation or just a few forged certificates slipped through the cracks, it illustrates how black market dealings can undermine public health and counter attempts to curb the spread of COVID.

The seven suspects could face fines equivalent to hundreds of dollars and even face five years in prison, but as Business Insider reports, this wasn't the only black market racket that helped people pass themselves off as healthy, and others yet have found ways to alter the results of their own positive coronavirus tests.

One anonymous man confessed to The Lancashire Telegraph that he did so in order to travel to Pakistan. He argued that it's too difficult for non-essential workers to schedule or pay for the COVID-19 tests mandated by U.K. airports, especially when traveling on short notice.

"You can simply get their negative test and change the name and birth date to your own. You also put a test date on which is within the time limit required," the man said. "You download the email, change it and then print it."

In a dizzying display of circular logic, he added that anyone who reports having coronavirus symptoms has a harder time taking a test, making it impossible to travel. But even U.K. travel agents are getting in on the grift — another anonymous traveler told the Telegraph that one agent offered to doctor a positive test so they could fly.

All in all, it's unfortunate that people are going to such lengths to make and keep travel plans, undeniably putting everyone around them at risk in the process.