Change and unintended consequences

From a Washington Post article, via Schneier on Security, concerning the prohibition of lighters and matches on commercial airplane:

As airports and government leaders began discussing how to create flame-free airport terminals, the task became more complicated. Would newsstands and other small airport stores located beyond the security checkpoint have to stop selling lighters? Would airports have to ban smoking and close smoking lounges? How would security screeners detect matches in passengers’ pockets or carry-on bags when they don’t contain metal to set off the magnetometers?

Just goes to show the importance of considering not just the first order effects of decisions and change, but the second and third order effects as well. Nothing is ever as easy as it seems, and we should not forget that (especially in the world of Knowledge Management).