These instances of "unintended acceleration" are due to the same thing that they have always been... people are stepping on the wrong pedal. That was the case with Audi's in the 80's and that is the case now.
Car brakes are stronger than car engines... period. That's why even highly modded Turbo Buicks can spool up by foot braking. If your accelerator sticks wide open and you step on the brakes your car will stop.
Car and Driver tested a Toyota Camry, an Infinity G37, and a Roush Mustang to see if they would stop with the accelerator at WOT. For the Camry and Infinity, braking distances from 70MPH and 100MPH with the car at WOT were barely more than normal. The Camry even slowed to 10 MPH from 120MPH before the brakes gave up.
Even the Mustang (540HP) could be brought to a stop at WOT from both 70 and 100MPH.
This runaway Prius douchebag is a liar who is trying to get a good seat on the frivolous lawsuit gravy train. A Prius has, what, about 6HP? Like that potent powerplant would be hard to reign in.
Funny how he's had the car since 2008 yet it conveniently waited until now to act up.
And as for the rest of them... there's what, about 8 trillion Toyota's on the road, yet we have only a couple hundred cases of unintended acceleration? If there really were something wrong the odds are we'd be seeing more than like a .00001% failure rate.