<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by Spider:
So, there is no way for immigration to tell whether a passport is stolen if the scanned data matches what is printed on the front page of a passport?</font>
Correct. IIRC, the idea of machine readability was to speed up the entry process and reduce manual input errors. Once scanned, the data is checked for naughtiness (i.e reported stolen) and then throws up a warning.