I had my 06 at the dealer today based on mileage (routine service) and in response to the accelerator pedal recall.
The "fix" was to remove the rubber floor mat that I keep atop the factory mat and to thread two daisy-chained black cable ties through the factory mat anchor holes and attach them to the seat supports.
The only thing missing from this bit of southern engineering was chewing gum and duct tape.
With the cable ties passing through the anchor holes there was no room for the anchors; the mats were resting atop the anchors. I promptly removed the cable ties, re-anchored the floor mats (because if they haven't come off the anchors in four years, I think they're not likely to) and reinstalled my thin rubber mat. It, too, has not caused a problem by bunching up under the accelerator pedal in the past four years.
I have measured the distance between my accelerator pedal in all positions and my rubber floor mat at random time intervals since I first learned about this problem. The rubber mat moves forward at an (estimated) inch in six months if not pulled back -- but it is pulled back frequently as I remove it to shake it out or scrub it. The worst case I found was with the rubber mat in its normal position: four inches of clearance. This happens to be the same number as on my 06 Avalon before it was "fixed" with a shim and a shortened accelerator pedal installed. The dealer also installed new firmware in the Avalon (but not the Prius) computer so that if the brakes are applied while the gas pedal is depressed (triggering parameters not specified) the fuel flow will be constricted or shut off and the car will slow. If the computer functions properly, that is.
I can't speak to the cause of Toyota accelerator-pedal sticking because I don't know the floor-mat configuration or other characteristics of any Toyota that has experienced the issue, or the circumstances of its driver, but I have serious doubts about the floor mat being involved, if only because people have been putting double floor mats in cars since about 1897, and today everybody does it.* The practice doesn't seem to have caused much of a problem. At first I dismissed the claims of people who said they could not shift into neutral, but of course the same computer that controls acceleration controls the transmission. Still, unlike the self-styled experts here, I do not claim know what the problem is. I'm not convinced, however, that Toyota knows. either.
This issue in and of itself is insufficient to put me off Toyota cars; mine have been excellent. Toyota's weaselly, procrastinating, and prevaricating response to the issue, however, could do that.
Davoud
*Don't bother telling me that _you_ don't do it; instead, spend the time studying "figurative speech."