If you don't want all the candy stolen, hand it out a piece at a time. Everyone knows that if you leave it out, it's going to probably get stolen. In fact, there's a legal terminology that has been used to go after people who do these types of things, it's called an "attractive nuisance."

You don't get to create a situation that a reaosnable person knew would lead to theft and then act like you're not in the wrong. Same with shitty drivers, you tailgate someone and they slow down to stop to make a turn, you run into them, that's on you.