I think the aggressiveness depends on the particular location. In the last year I've rented cars in Richmond, BC and Honolulu, and in both locations they were super laid-back about little dings and scrapes, even one scrape that I knew damn well that I put in it while wedging myself into a tiny spot in a parking garage.
I came right out and told them about it when I returned the car, they looked at it and said "No biggie. We'll let you know if it's going to cost anything to repair." Then I spent the next four days worrying they were going to charge my credit card $300 to fix a tiny scrape, but they called me on the fourth day and said that they weren't going to charge me a cent.