My brother once had some problems while he was a Physics professor for He did refuse to approve a guy's test where the guy, in one of the questions (one more right answer would've merit an approval) used the required formula correctly, but for he mess up with the units the result was wrong, so the guy took the complain to the student's board, which in turn took it to the faculty; but my brother's defence was quite simple, he said that if the guy had some common sense he should've realized that something was wrong with the unit system, for the question was something like this: A football player (soccer of course <g>) runs at certain speed in certain direction toward the ball, which is travelling a certain speed in some certain direction (all speeds and distances where not given in same units, some where meters, some km, some seconds, some hours, classic stuff, and all reasonable speeds for the scenario) and the guy came up with an answer of some trillions kilometres, and although we have some big stadiums down in Argentina, not even one comes close to that size <g>