The issue likely has more to do with the point of sale rounding partial cents rather than Chipotle knowingly stealing pennies. Assuming a 7% tax rate, the tax in the last example was not 1.24, but 1.2425. Some POS systems always round up, others use bankers rounding, and others use normal mathematical rounding. The issue of rounding is way less interesting than you may think, but it's also likely more complex than you've ever dreamed.