Permissions is the keyword here. There are many ways to make sure ppl cannot actually use the textures inside your product. If you bought your textures, sellers of these textures, often explain in their TOS of their products how they want you to set the permissions to avoid abuse/theft etc. Some want the perms set to just Copy, no Transfer nor Modify. Some allow other configurations like Copy AND Mod, but NEVER Copy-Trans AND Modify. I. myself, mostly make my textures just copy coz my products sometimes need to be adjustable by a menu and I don't want customers to risk losing my products by screwing them up and not having a backup item. I also set my scripts to just Copy for this reason.