You're missing the point (not surprisingly).
The ride, while in motion and apparently scraping the edge of the pit, is not the direct cause of concern.
The concern arises when the ride is e-stopped, either because of an automatic sensor sensing too much restrictive pressue put on the motors, or because a cast member hears something they don't like (the scraping) and hits it, or maybe both.
E-stops are designed to VERY QUICKLY shut down the entire system. They're designed that way because you have to plan for the worst possible cases, which would require immediate ending of all motion. When you E-stop, you don't coast to a stop. In an attaction like this, you STOP.
What happens when little Timmy is flying high above Circusland without a care in the world, and an automatic sensor literally SLAMS the brakes on??? Little timmy could fly forward and hit the cab. Or the joystick.
Let me make this clear: The issue isn't the paint being scraped off. It's the cascade of possible effects that restriction could cause.
And FYI... I have a history in Ride Operations Supervision. So I know what I'm talking about. That's not the line of work I'm in anymore, but that's what I did. And e-stops and their consequences were a daily issue I had to deal with.