A couple of years ago parents of one of my daughters friends bought a nice large home. To save money they rented a machines and had just finished when we went to pickup my daughter. They were a little embarrassed to get caught but I understood the need for them to save money just taking on a larger payment.
I had to bite my tongue the carpet was so wet, when the walked out of the room I bent down a took a swipe with my hand. It was soaked, I mean bad, heck water losses we do are not left that wet. I felt bad for them and mentioned they should get some air on it and maybe a dehumidifier if they owned one. They questioned my concern and stated that the carpet was really bad so they went over it several times.
Talk about mold, I was woried about subfloor damage, the carpet was already buckling from the excess moisture. Not sure how long it took to dry, but sometime it's better to spend a little money. Not saying the should have called us but even Stanley Steemer could have done a much better job than a grocery store rental. Even being the NASA approved machine didn't help.