Wow, did not see that coming. But then again it is good to see Google being open and honest about this. I am sure it has happened to the other big players: yahoo, msn, and live. But you don't see them coming out about it (that i am aware of).
it might be another one of there human error things. i remember not too long ago they said that every single website contained viruses because they accidently added "/" to the list of infected sites