It is possible to break our clutch. It took a lot of abuse for this to happen. The Pressure plate is the OEM RS4 pressure plate that all of you have on your RS4 from the factory. We have been using the pressure plates for the B5 S4, B6 A4, B6 S4, B7 A4, B7 S4 and B7 RS4 for years and the straps have never broken because of a manufacturer defect. They have all broken from driving the car past it's limits.
If the pressure plate failed first, it could cause the slipping. However, that means he drove the car while the clutch was sipping for an extended period of time.