They’re out there among you and you don’t even know it. Walking the aisles with you, checking the sales with you, then disappearing into the ether, into their Mazdas and into the mist.

You’ve heard about them. Maybe you’ve even seen one and not known. And yes, you’ve wanted to be one. After all, these people get paid to shop. You can do that. That’s even easier than playing video games for a living.

But deep down you know they’re in the shadows for a reason. Like the FBI or the CIA, Mystery Shoppers shroud themselves for a reason. Because they’re protectors, too. They wear masks of anonymity to protect your customer experience, but it wasn’t always this way.

The concept of mystery shoppers originated in the 1940s when research company WilMark hired private investigators to measure employee integrity in banks, retailers, and other businesses where money exchanged hands. Money that goes missing is not good for business. Nor are businesses that create unsafe environments for their employees or shoppers.

As companies began to focus on increasing customer service as a means of increasing sales, the role of mystery shoppers shifted from measuring the trustworthiness of workers to assessing the customer experience in a business (and eventually on a business’s website).

Today, mystery shoppers are often tasked with recording audio or video of their visits, or asked to fill out surveys as another means of recording their “shop.” And said “shop” might not include buying anything at all, but instead feature questions the shopper must ask, or complaints they must lodge, all to better gauge how a customer can expect to be treated whilst shopping.

Additionally, while shopping brings to mind images of department store bags and long receipts, mystery shoppers hide out in many industries, including: banks, theatres, car dealerships, hospitals, concerts, shopping malls, retail stores, call centers, hotels, restaurants, parks, gyms, spas, franchising operations, government organizations, churches and airlines, at least according to Job Monkey.

But I know the real question on your mind is: How can I become a mystery shopper? The simple answer is, you apply. Or request. Or sign up.

You don’t need special qualifications, you just need to be prepared to review businesses more stringently than you might be accustomed. But there is no secret fortress to infiltrate, no society to assimilate into, no language or code words (at least that I’ve yet found). You just apply and do it, same as anything else.

And yes, you can make money. How much is the same as for any other job; it depends on how much you work, how well you work, who you’re working for. But it wouldn’t be a business if it didn’t make somebody money.

So the next time you go to the store, masked up at the time of writing, take a look around and ask yourself if one of them is out there. And take a look at yourself in your trip. Did you find everything you needed? Were you greeted with a smile? Do you feel like you and your money were valued? If you have answers at the ready, then maybe the question is really, why aren’t you a mystery shopper?