I would have taken those home too! I love seashells. There are tons of them in our bathroom, in various glass jars, bowls & vases. I've been collecting them for over 50 yrs.
I'll never understand people who put perfectly good things in the trash just because they don't want them. First, the landfill issue. And second, it seems incredibly snobby and selfish to me. Things that could be donated to charity. Seashells (especially in FL) don't fit that category, but I see all kinds of things at the curb on trash day that broke people would love to have. I'm not above bringing curb stuff home, especially when it's a nice upgrade for something I already have, and anything that can serve as a plant stand.
I brought a wood headboard & footboard home once & DH made a bench out of them. I have a beautiful bentwood chair on my porch that was curbside because a dog had chewed one of the legs a little bit. Once I found 4 like-new plastic stacking chairs. Lots of flower pots, a couple of baker's racks, various little tables, a couple wall shelves, a beautiful upholstered foot stool with wrought iron legs that are kind of rusty on the bottom, baby pools, an antique wood ladder, plastic stacking drawers, tomato cages, probably other stuff that doesn't come to mind at the moment.