If it's driverless car hits you, it'll glue to you to the car......
I can just see it, the Google car bumps into you gently, you fall over onto the car and it glues your clothes, hair and skin to it, takes 3 hours for someone to free you (or even a trip to the hospital), ruins your clothes and your hair do all in one go.
Yeah, I'm sure in a serious incident people would much rather become a hood ornament than go bouncing under a truck...
But, honestly, did Google really think that one through???