Actually no. The reason Google's cars do this is because they (for now) drive in California. The driver's handbook in California explicitly states that you should at all times keep up with traffic, even if it means exceeding the speed limit a little bit, so that all cars are driving at roughly the same speed. You won't get a speeding ticket, because you are following the law. Presumably, in other areas, the car will be reprogrammed with knowledge of that area's driving rules, and will or won't do this as appropriate.
Wow, is that true? I drive in Cali, I guess I should know that but it's been so long since I looked at the handbook. On my last speeding ticket, I did tell the cop that I was merely traveling equal to traffic, and he shot me a look like I was an idiot. If I knew that tidbit, I might have tried to fight the ticket.