I wouldn't bother with a release. The chances of people recognising themselves are close to zero and even if they do, the chances that they will even consider doing anything about it are also almost negligible. If you look at postcards for sale of normal tourist places you will see that many have people in them of a similar scale to yours where they are in the scene but are not the subject. I doubt that the postcard manufacturer has releases for any of them.
Let me know when you start selling those!
Originally Posted by Worker 11811