My first new car (1976 Ford Pinto Stallion) had a set of Firestone Steel Radial 500 RWL tires on it. I ran them at sidewall maximum inflation for about a year. One day I decided to try the owners manual pressure instead. Driving down I-65 at an average speed of 65 to 70 mph (yes, the speed limit was 55 in 1977) the entire tread row of the left front tire peeled off really making a mess out of the left front fender and scratching up the left door and rocker panel as well. The other three tires had broken cords in the sidewalls and would make the car physically wobble going down the road. I learned two important lessons from that experience.
Lesson 1: Firestone would not stand behind their product. I've never bought a Firestone tire since then.
Lesson 2: While the tires do tend to ride more firmly (harder), they last longer and give better fuel economy.
If you want to talk about a safety hazard, the Firestones on my Pinto should have trained the company (there were lots of lawsuits over that tire) to make a tire that the tread row wouldn't peel off of. The Ford Explorer fiasco was using Firestone tires that the tread peeled off of. Firestone tried to claim they were underinflated. Underinflation is a serious safety issue, but I don't agree that overinflation is a problem.