Sorry to disappoint, but this is only about polygraphs. Last week, when Senator Rand Paul suggested that the White House subject its employees to lie detector tests to unearth the anonymous Op Ed author, we realized that some employers might get the idea that this is an excellent way to finally figure out who keeps stealing Bob’s lunch from the company fridge. Slow down Super Sleuth. Before you strap on the electrodes, you need to know a few things about the federal Employee Polygraph Protection Act (EPPA). That’s right, we’ve got laws for every occasion.

The EPPA has been around since 1988 and practically prohibits employers from using polygraphs altogether with only a few narrow exceptions. Employers cannot require, request, suggest or causean employee or applicant to submit to a polygraph exam. And if an applicant or employee refuses to take a test, employers can’t use that as a basis for firing or not hiring. The narrow exceptions include public employees and employees of federal contractors engaged in national defense. So, Rand, you are good to go.

Private sector employers are permitted to use the polygraph only in connection with an ongoing investigation of an economic loss, believed to have resulted from theft, embezzlement, misappropriation or industrial espionage. See, you may be able to recover Bob’s misappropriatedlunch after all. Employees cannot though be lined up and forced into the hot seat. An employer must have reasonable suspicion that the specific employee to be tested was involved. In fact, the employer must prepare a written statement to be provided to the suspected employee, specifically articulating the basis for the suspicion and demonstrating that the employee in question had access to the stolen property. The employee must also read and sign a “your rights under the EPPA” document which makes clear, among other things, that the employee can stop the examination at any time. At the end of that process, even if the employee fails the polygraph exam, that result cannot be the sole basis for termination. So even if according to the polygrapher (not a guy with multiple wives) determines that Bob actually stole his own lunch to get the company to pay for a better meal, the employer must have additional supporting evidence before it can terminate him.

Keep in mind that although we often refer to lie detectors and polygraphs interchangeably, the fact is that the machine is not really a truth getting device. Polygraphs measure physiological reactions, heart rate, respiration and perspiration in response to various questions. A responsibly administered exam can certainly suggest or imply whether a subject is telling the truth, but not to a certainty. Enough treasonous spies in this country, including Aldrich Ames, successfully passed multiple polygraph exams. So before you go all Meet the Parents and hook up your future son-in-law to the machine, remember, you might just be making him nervous.

As for the lunch thief, they make these really small surveillance cameras these days. Stick one in the kitchen. Yeah, that’s legal.