Caligula - OK, I agree that some of them might not bother going, but I bet some would have paid, and even if it was just 1 in 4 then it's still a significant enough sum of money.
I just don't see why some folk should feel it's Ok to be dishonest and let other people pay for them.
In a town near where we live there used to be a summer music festival run by a charity. It was good fun, with some quite good music & bands. But because it was run in the local park, it was hard for them to restrict it. They had a perimeter fence, and tried to put the stage at an angle so it wasn't very visible outside, but it wasn't perfect. On the first year loads of people went, paid the entrance fee and it was a huge success. Two years later, some people were still going, but many went up on the hill behind the park instead and watched from there (for free). By last year, a whole host of food vendors/ chair suppliers etc had made the hill an informal 'freezone' (so people would pay £5 for a chair, but not for a ticket ). This year the festival isn't happening - the charity went into deficit simply because people were 'cheating' the system in this way.
It's very simple - the more people let themselves believe that this kind of 'grey theft' is OK and justifiable, then the more likely everyone will lose out in the long run.
It might seem like a small, insignificant act, but if replicated across a massive population and applied to many situations, this sort of behaviour has major societal implications.