THERE are many reasons why you might have been stopped at an American transport hub and your bag searched by officials. You might have be chosen at random. Perhaps you matched a profile. Or you could have been flagged by an airline, railroad or security employee who was being secretly paid by the government as a confidential informant to uncover evidence of drug smuggling.

A committee of Congress heard remarkable testimony last week about a long-running programme by the Drug Enforcement Administration. For years, officials from the Department of Justice testified, the DEA has paid millions of dollars to a variety of confidential sources to provide tips on travellers who may be transporting drugs or large sums of money. Those sources include staff at airlines, Amtrak, parcel services and even the Transportation Safety Administration.

The testimony follows a report by the Justice Department that uncovered the DEA programme and detailed its many potential violations. According to that report, airline employees and other informers had an incentive to search more travellers’ bags, since they received payment whenever their actions resulted in DEA seizures of cash or contraband. The best-compensated of these appears to have been a parcel company employee who received more than $1m from the DEA over five years. One airline worker, meanwhile, received $617,676 from 2012 to 2015 for tips that led to confiscations. But the DEA itself profited much more from the programme. That well-paid informant got only about 12% of the amount the agency seized as a result of the his tips.

While the DEA and its informants may have profited nicely, travellers no doubt paid the price in increased searches. We have no idea as to the extent of the problem because the DEA did not keep records on tips and searches that did not lead to seizures. As Justice Department Inspector General Michael Horowitz put it at the tribunal: “We don’t know, for example, whether they were batting 1.000 or batting .050.” For every successful seizure, there might have been 10 passengers inconvenienced by a search. Or 100. Or 1,000.

That is not merely an inconvenience. It is probably a violation of protocol and the law. According to the Justice Department report, paying TSA employees to spy on travellers was a clear violation of DEA policy: those working for law enforcement agencies in their official capacity can’t also be confidential sources. Likewise, encouraging TSA and other employees to search bags and parcels may have infringed people’s constitutional protection under the Fourth Amendment, against “unreasonable searches and seizures”.

The DEA’s chief of inspections told the congressional committee that the agency has stopped making payments to government or quasi-government employees, and that it is reviewing its use of “limited use” informants. But the damage has been done. Business travellers have already had to put up with the TSA’s inability to handle passenger flows, mockery of their ignorance, gross misconduct and failure to detect threats. Now add another one to the list: excessive searches of their belongings in exchange for secret kickbacks in violation of protocol. That the directive came from a government agency and included a slew of other organisations and entities doesn’t make it any better.