Trust me, as a former journalist, you're wrong about this. There most certainly is a right to this kind of privacy in public. If there weren't, I wouldn't have had to get so many people to sign waivers that allowed me to use their photos.
James, I don't want want to beat a dead horse, but there really should be some clarity here. I'm just thinking there's some confusion regarding wording.
No journalist in America has EVER needed a waiver (aka model release) of any sort to use a pic of a person in a public place OR during a newsworthy event. During a newsworthy event, you are legally able to jump a private fence onto someone's private property to shoot pic of their house burning down. A journalist faces NO civil liability, and can only face criminal charges if a cop orders him/her to move for safety reasons and he/she refuses. I know first hand, since I've been thrown in the back of patrol cars by rookie cops a few times. Journalists need to maintain relationships with cops, and yellow police tape issues need to be resolved prior to emergencies...and they usually are.
Imagine covering a contentious town hall meeting and shooting angry protesters and having them be able to say, "You can't use my photo because I'm not signing a waiver!"? They may be able to make it difficult to ID them, but "refused to be identified", makes a news statement in itself.
Another example: say you take a photo of your hated neighbor tripping over a crack in the sidewalk. He has a stupid look on his face and his big belly is showing, and it's probably the most embarrassing photo ever. If you sell the photo to a newspaper as a feature or news picture, you are 100% safe from any legal action. Sell the same photo to be used in an ad for concrete repairs and you and the business are liable for a law suit. News vs. commercial use. You don't even have to be a photojournalist to fall under the same protections as a photojournalist.
Photojournalists get names, ages (for kids), and home towns solely for the purpose of good captioning. Period. Editors hate photos which aren't ID'd. It's a sign of lazy work.
Again, photojournalists NEVER need waivers for covering news stories, and especially not for taking photos in public places. Journalists with pen or camera are protected under the First Amendment of the US Constitution, which addresses freedom of the press very specifically.
If the OP posted the photo on a commercial website with the clear intention of having the image result in a profit, then the subject would have civil recourse. It would be limited, however, to the range of financial benefit. If she made $20 of ad revenue, then she could be liable for $20, or perhaps three times that amount in some states. I'm not a lawyer, and only know the general principles. Further, if the photo was used in that same forum in a derogatory manner, then a punitive award could be made. AW, btw, has an enormous level of protection because of the presentation of its informational value, even when it comes to lighter subjects, in the same vein of college newspapers.
Courtesy, politeness, and accurate captioning are a different beast.
ETA: and this is all speaking ONLY to US laws...