TANSTAAFL and the Opportunity Cost of "Free Tickets"

From Michael Munger, Chairman of the Economics Department at Duke University, comes this little tidbit on opportunity cost (by way of Joshua Hall over at Division of Labour):

The face value of a basketball ticket to Cameron Indoor Stadium is $40. But for most games one could get a lot more than that. For some games, in fact, like Duke vs. UNC, the value of a scalped ticket is well over $1,000. In 2006, the value was more like $2,500. So, when faculty ask me (as department chair) for a raise at the end of the year, I will remind them that they don't need more money, because they are already rich.

"What do you mean?" they ask.

I reply, "Well, you can afford to spend $2,500 to go to a basketball game. You must be wealthy."

They show me the ticket. "$40! It's a $40 ticket!"

My response? "Tell you what. I have $50. Will you sell me the ticket for that price? After all, you claim it's a $40 ticket."

So far, I haven't been able to buy any tickets that way, even from people who tell me that opportunity cost is a stupid concept.