That must be the main cause this happened.
I'm glad everyone came out more of less safely.
Many years ago, my friend and I rode Tornado (a Vekoma corkscrew so similar to Python) in Walibi Belgium with our harnesses not clicked. I must have been about 15 years old or something and although we yelled and opened our harness on the lifthill, the ride was not stopped so we closed the harness again and held on tight and rode Tornado. Due to the whatever forces, we took the corkscrews without any problem and arrived safely back in the station.
Luckily this did not happen on a coaster with air- or hangtime.