Still, it is in public, one should expect to be seen in public.
I'm more concerned about people that point cellphone cameras around at awkward angles on public transportation. I find that much more disturbing than the thought of street view catching me scratching my arse when I thought no one was looking.
Regardless, I'm glad to have it here. I think it is a good thing. Anybody who is having sex in front of their picture window (as I know that argument is next) wants to be seen. If they don't, they can close their curtains.
Google also publicises the dates and times of their sampling. I think they are showing due diligence in protection of privacy, and the value of the product far outweighs any individual embarrassments.