No such thing as a free...paper?

So when you pay thirty-five cents to get a newspaper out of a box, what is keeping you from takin all the papers sitting there? More importantly, what do newspaper publishers count on preventing you from stealing their revenue-makers? Does a newspaper have such a steeply diminishing marginal utility that two are just not worth it? Is the cost of carrying around so much paper not worth it? (but there's arbitrage, you could resell). Or are they banking on the goodness of the hearts of the upper-middle class professionals who mostly buy papers? Hmm.