Our church really struggles with this. We have potlucks in the park during the summer, and these are not supposed to be evangelism events or designed to be "open to the general public," but fellowship events. However, at every one, we get a number of kids, and sometimes adults who will walk right up and just help themselves, usually without asking. They don't want to stay and be a part of our group or learn about our church (we invite them to participate), they just want the free food, then they wander off, taking their heaping plates of food with them. The struggle comes from wanting to be Christ-like, yet also not wanting to encourage behavior like you mention where we enable things that aren't good for people, if you know what I mean. Sometimes, it's hard to know where that line is.
I am just as conflicted by the food bank run by one of my local churches.
Looking at the manner of dress, the cars they drive, etc., I am guessing most of the people who show-up really don’t need a food bank.
But we probably have to tolerate that B.S. in order to ensure that the folks who really DO need help get it.
Simple. Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime. If they refuse to learn to fish, they are stealing from you. The Bible says, "Thou shalt not steal."