If one has no reasonable expectation of privacy while out in public, why are faces so often blurred out in photos and video? For example, on Google Earth.
There are hundreds of jurisdictions in the world with various approaches to privacy in public places.
It is simply much cheaper for the publisher to avoid claims in the first place than to hire lawyers to deal with them. Even if the publisher has full legal standing to publish the faces, it would not always be able to recover costs from the failed claimants.
Faces on street views do not add much (if any) value to the service anyway. Conversely, they often upset and make unhappy the owners of the faces.
Say you are writing an article about someone accused or convicted of fraud. You have one photo of them; showing them, their ex, and an unidentifiable third person.
Publishing the photo unaltered could lead to a defamation claim due to the implication that these people are associates of a criminal or have benefited from their crimes when the ex might have ended the relationship well before the crimes and the third person might be a random person at the party.
There is at least 2 possible reasons for it.
When taking pictures of many, many people, there is a near certainty that at least some of them will become famous at some future date. Which will allow them to control the rights to their likeness and image. In the US, this is not covered by the federal law, but according to rightofpublicity.com, 24 states have some sort of "right of publicity" laws. Since it's not possible to go through all the pictures which will have been already distributed at that future date, the prudent thing is to limit such distribution at the source.
The second reason would be to protect the privacy of individuals who have relocated and are in hiding from former abusive partners, or even from former criminal connections. A public picture of them at a certain location can put their life and well-being at risk.
While people may not have an expectation of privacy (and you don't need to blur out your personal pics) in my/most places if you are publishing photographs of people for non-editorial purposes - you need a model release or people who's image you have appropriated may be able to come after you for $$$