I used to have a thing about benches. Now its beach chairs and umbrellas. At least I'm progressing.
When I take photos of random people on the beach, I try to remain conscious of their privacy, lest I have them sign a release form. But when it comes to objects, everything is fair game. I once did a commercial beach shoot. There was so much involved, from legal to logistics. I prefer just to walk around and take pictures of interesting things, or people.
Putting people or chairs in a shot causes us to imagine ourselves in the scene. If we see people, we subconsciously become them. When we look at chairs, in our mind's eye we find ourselves sitting in them. We project ourselves with our thoughts without even realizing it; it's a habit we all have. Sometimes I feel I've been somewhere having previously only looked at it in pictures or videos. But, as they say, there's no substitute for the real thing.