[julian_t]

Fortran, not COBOL, but I came across a similar thing when helping to update code for Y2K. An insurance company used a 2 digit field for year of birth, assuming that it would always be prefixed with '19'. I sort of forgave them because the code had originally been written in Fortran 2 sometime in the 60s, and who would ever assume that their code might still be in use 40 years later?

[trealira]

In the 1960s, there were still 70 year olds born in the 1890s, and 80 year olds born in the 1880s, so it still doesn't seem like a good decision even for something written back then.

[nikau]

In 1966 a 7.25MB drive cost $25,510.

In todays money that's $246,316.70.

So it would have cost 6 extra cents for every date entry.