Fortunately, I clean carpets...
The young lady who knocked on our door was friendly, sweet and cordial. No hard sell. Of course, I've been in the industry nearly 30 years so there wasn't much point to a free room of cleaning.
If you're curious about how the system works, look them up on YouTube. The fellow I watched said, "I like a good quarter-inch of foam on the carpet."
Imagine working up a good lather next time you shampoo your hair.....and, then not rinsing it.
That's exactly what I saw this fellow doing. Scrub in the foam and then leave much of it where it lays.
If you've ever had problems with a stubborn carpet spot that kept coming back, and you've been using a nice foamy cleaner, the odds are good it's because of that foamy stuff. It's not just foamy, it's sticky. It's supposed to be. It's the detergent in the cleaner. Detergents are designed to be sticky to grab the dirt. They're also hydrophilic, or "water-loving," and are meant to be removed with a water rinse because they'll hang on to water, too. When you don't rinse you can be creating a rapidly resoiling headache.
Imagine running your fingers through a head-full of day-old, dried up shampoo. Yeah, yuck.
One of the fastest ways for a professional carpet cleaner to guarantee little repeat business is to intentionally leave sticky, foamy, dirt-attracting residues behind. It doesn't look good when the carpet needs cleaning again in a week or two.
It's not so good for your carpet or the family, either.
Thanks but no thanks.