Hi JMP,
As good Bill alluded to above, if the image is not for sale or profit, or use by a third party outside of editorial news journalism, then the persons, objects and buildings are technically in the "public domain", and no release is required. If you want to sell it as "Art" or shoot private/commercial property, then things can get tricky.
If the yard sale was on someone's private property, or on the property of a commercial business where the business name/sign was clearly visible, then a property release would be required if you wished to use the photo for PROFIT reasons (mostly because you, as the photographer, do not own the COPYRIGHT to the building/house DESIGN. The architect does). Again, this does not include photojournalism (as PJ is considered in "the public interest". This is why the National Enquirer shoots everyone, everything and everywhere in public with their only problem being libel/slander suits if the image is considered "defamatory" by the persons depicted).
I believe (correct me anyone) that prvate/commercial property only extends to the beginning of the sidewalk (which then becomes "public" or city property, and you CAN shoot anything and anyone on this little concrete strip of "public domain"). But since you were attempting to shoot something actually on on someone's "private" property, then of course they could yell at you to stop. But since you are also a "private" citizen with rights, you could stand on the sidewalk (so as not to trespass), shoot and exhibit the work, but risk, without a property release, a threat or action of lawsuit.
But I also believe that if the HOUSE/Commercial Property (which is under copyright by the architect/designer) as A WHOLE is not CLEARLY RECOGNIZABLE, then you have nothing to worry about. If the house in whole or the house ADDRESS does not show up in the photo, there's no real proof that the house in quesiton was TRULY the house in question ("Hey Judge, there are hundreds of those wrought iron fences around town, and at Home Depot."). And you could argue this unless they themselves took a digital shot showing what you shot, and drag you into the People's Court to be castigated by a crazy ex-judge while waving their "proof". But a real judge would not side with them unless the copyright owner of the house (architect) showed up and joined in as a plaintiff, or, the homeowners tried to claim trespassing (which, if you were standing on the sidewalk, would fail in court as a claim against you).
So, interestingly, the home owners may "own" the house and property (as well as the air inside of that space), but they do not actually own the COPYRIGHT of the house (which is where the whole issue of Property Releases truly belong). The design copyright belongs to the designer and architect. So do homeowners really have any rights against you photographing something they had no hand in designing? Just the right of "private" property, which really belongs to the architect or the bank that holds the mortgage. And they ain't gonna care!
Also, the house or commercial establishment has to be CLEARLY recognizable so that the plaintiffs could infer some form of defamation or lack of permission/release, and the judge would have to clearly determine whether some form of "harm" actually occured. And since the homeowners don't own the copyright, they can't sue you.
Homes should still be generally avoided because of this complex copyright/release matter, unless the home "owners" give you permission to photograph their fenced goods. While this does not explain all the bus-riding-tourists (and the bus companies who take them there) who photograph the homes of the movie stars in Hollywood without getting busted or sued en masse, as a visible photographer it's something to be aware of. My motto is shoot first, then ask questions later as you run like hell to the darkroom.
PS: If anyone has more info to correct anything I've said, FEEL FREE!
Cheers,
Chris
canonetc