Wait is it actually that deep though. Like if someone leaves a plant on their front porch or at a shared office, snagging a tiny snip feels harmless. Plants grow back. Unless it's some crazy rare expensive cultivar, it's basically sharing.
My cousin in Florida always leaves her pilea plant on the front steps. She calls it the sharing plant, but I watched someone snap off three leaves without even knocking. Does it count as sharing if the person taking it never interacts with the owner. Even a common plant feels like someone's property, not just free stuff. Where does that assumption come from, that anything left outside is up for grabs.