Not just the Prius, many (if not most) cars are like this now.

There was an interesting incident (Miami, I believe) where authorities discovered a 'pirate' radio transmitter. Turns out that over the previous months, quite a few cars had to be towed from the nearby parking lot because the touchless keys did not work (and there was no mechanical override), often resulting in the (quite expensive) replacement of the computer. Apparently the poorly designed transmitter was interfering with the encryption handshake from the keys.