This doesn't match my experience, and I run a photo community myself. You're absolutely right that people are generally fairly clueless about licenses, especia

This doesn't match my experience, and I run a photo community myself. You're absolutely right that people are generally fairly clueless about licenses, especially in the amateur domain. And the main implication of that is that they don't bother with it at all and leave it at whatever the default is, which typically is "copyrighted, all rights reserved". Those explicitly tinkering with licenses, which is a purposeful action, tend to actually know (somewhat) what they are doing. Further, if you leave a photo's license to its default, copyrighted, absolutely nothing stops you from sharing it with friends and family. What would happen? You share it with them and then sue yourself? Similarly, somebody you don't even know could use your copyrighted image and post it on social media. Again, nothing happens, as this is widespread behavior and called "fair use", which it legally absolutely isn't. But nobody cares, as nobody will sue over it unless there is a case of vast commercial usage.