I actually learned of the difference between the U.S. Survey Foot and the International Foot while working on https://plantpredict.com https://plantpredict.com.

I actually learned of the difference between the U.S. Survey Foot and the International Foot while working on https://plantpredict.com https://plantpredict.com. For years we had infrequent but bizarre unit-conversion bugs. Calculations literally weren't adding up. We assumed it was related to precision rounding since numeric input fields showed rounded values. It turns out the imperial-to-metric feet conversion factor we picked was 1 of 2 choices, and we picked wrong!