Curiously, even throwing open the borders does little to address the call to care for the weak and the needy because there's still no additional information regarding who is actually needy.
I remember spending a long weekend in Paris, several years ago. The first morning I was there, a Saturday morning, I was horrified to see the state of some of the beggars lining the Champs-Elysees. The first one I saw was a man dressed in rags, barefoot and dirty, all but prostrate on the ground supporting himself with a stick, with his hand extended as he begged. I'm no stranger to seeing street beggars having lived in other cities but I'd never seen anything like that. But curiously, a few yards further along, was another man all but identical in appearance. And another, and another, and so on. Come Monday morning there wasn't a single beggar to be seen.
I've also personally watched street beggars in London with their hat on the ground begging for change. The contents of their hat are typically equivalent to no more than 50 cents or so. Yet if someone puts a larger coin in there (in England we have counts for one and two pounds, worth about $1.50 and $3 respectively), they wait until they think nobody is looking and remove it.
How to tell the truly needy from those just trying their luck is the tricky part. Unless the objective is simply to throw money at anyone who cares to ask for some (in which case perhaps someone could show me where I sign up, because it seems easier than working for it), some kind of processing is required.