From Strib: Airport sign cost jumps past $2 million. Probably should make clear that it is more than one sign, not clear from the article how many though.
Faced with complaints that an estimated 20,000 people show up at the wrong terminal each year, MAC has been considering proposals to change the terminal names on the signs and list the airlines that fly out of each terminal.
20,000 out of some 35,000,000 is about 1 out of 1750. If the 20,000 number is remotely correct, this does not seem to be much of a problem, as a commenter notes "you can't cure stupid". I suspect each of us goes to the wrong place more frequently than 1 out of every 1750 trips (or say once every two years). Another way of thinking about it is 1 passenger on every 10 flights showed up at the wrong terminal (and even that is rectifiable by taking the LRT between terminals if they got there early enough).
Of course signs are expensive, and it is important to convey information to travelers, but is there really a problem if only 20K out of 35M get lost?