In response to Toyota's unintended acceleration debacle, BMW engineers decided to calculate the equivalent horsepower of a 3-series' brakes: roughly 2,500 HP. That's right, every 3-Series ships with more than twice the power of a Bugatti Veyron.
The engineers arrived at the 2,500 HP number after measuring the car's 60-0 MPH deceleration time (2.5 seconds), then calculating how much horsepower would be required to achieved equivalent acceleration (0-60 MPH in 2.5 seconds). This is obviously an over-simplified number that exists merely in the calculations on an engineer's note pad - the rear-wheel drive 3-series would need extensive modifications to transfer that accelerative power then send it to the ground - but it does demonstrate exactly how much more powerful the brakes are over the engine, which, in the case of this Bimmer, makes between 200 and 300 HP.
What's this mean for unintended acceleration? Even if you couldn't shift the car into neutral, even if the throttle was stuck wide open, even if you couldn't turn the engine off, you could still stop the car by using the brakes, which can easily overpower the engine.
Think this only applies to expensive cars from Germany and not cheap cars from Japan? The 2010 Toyota Prius's 60-to-0 time is only a couple hundredths of a second off the BMW's figure, still giving it huge equivalent horsepower numbers from its brakes.
Why are BMW engineers crunching numbers in response to a Toyota problem? They're likely just as convinced as we are that the entire situation is caused by human error and, because of that, it could effect them too. In response to the threat of enormous lawsuits, they're quietly building a stockpile of evidence so they can conduct a sort of legal blitzkrieg against any potential aggressors.