Depending on the circumstance, a model or property release may not be legally necessary. But getting one never hurts and it may help. It may make some people think that they can’t sue you (they can, even if their cause of action is bogus). If they do sue you, having a release may shorten the litigation and it could help you win. Even when you win, though, your defense fees can be costly.
In those situations when a release is not required, other legal issues may be presented when photographing a person, an animal or other property. These include trespassing, trademark, false light or invasion of privacy. All of this can get confusing. That’s also why it’s dangerous to take anecdotal advice.
For example, if one person has a fashion shoot in a national park and needs a permit, it does not mean that all professional photographers who shoot in a national park need a permit. While some stock agencies may require a property release for an animal photo, it does not mean that it’s legally required. It means that they are being cautious in this litigious society.
I recently photographed some huskies at a public park. I wasn’t trespassing on public property, the dogs are not trademarked and I did not misrepresent them (also known as “false light”) in my photos. Further, since animals don’t have privacy rights like humans do, I did not need to get a model or property release from their owner. But I got one anyway. I asked the owner in writing for permission to use the photos. I did that that only to keep the owner from getting upset and to avoid any hassle with a stock or advertising agency.
What is often practical is not always legally required. To figure out the differences and to make the best decisions about what to do, talk to an attorney to discuss your particular situations.
Take my advice; get professional help.