I once went to one of the most honest dentist ever. He told me my teeth are perfectly fine but since I'm allow X number of visit per year on my insurance and their fiscal year is about to be up, he's going to schedule for all these extra cleanings. And I quote "Good for me but not completely necessary. You can cancel the appointments if you want but I just want to milk them for a little extra money and you'll end up with super healthy teeth in the end".
You wonder...how many doctors out there also milk the system. You get scared into an exam that may not actually be required? "Oh? You have a cough? Let's have an MRI and blood test done just to make sure it's not a rare bacteria" or some crazy stuff like that. As a result, insurance cost goes up. Other pay the bill.