That anti-counterfeiting measure (secret yellow dots encoding a serial number) was originally on color copiers. Then it got extended to color laser printers. D

That anti-counterfeiting measure (secret yellow dots encoding a serial number) was originally on color copiers. Then it got extended to color laser printers. Do we really know that it hasn't been extended to ink jets as well? I think the grandparent has a legitimate observation. It would explain why you need to have working color cartridges to be able to print in black and white. (It's obvious that paper money is not going to be counterfeited in black and white, but maybe they decided to hide serial numbers on all printouts, not just color printouts.)