Cultural capital among economics students

I discovered yesterday in class to my shock and dismay that a surprisingly large fraction of both my undergraduate econometrics students and my graduate applied econometrics students had never heard what I think of as the fundamental joke about economists, namely the can opener joke. Here is one version, taken from this website, that attributes the joke to Paul Samuelson:

A physicist, a chemist and an economist are stranded on an island, with nothing to eat. A can of soup washes ashore. The physicist says, "Lets smash the can open with a rock." The chemist says, "Lets build a fire and heat the can first." The economist says, "Lets assume that we have a can-opener..."

Seems like something every student of economics should know, if only because one sometimes hears references to it in economics talks and even in popular culture. And, of course, also because it makes a useful substantive point about economists.