What is "blue cards"

Usage examples of "blue cards".

He explained to the women that when they sat at their workstations for the first time and swiped their blue cards through the slot on the top of their keyboards, a prompt would pop up asking them for a password.

And we watched the jam as they surrendered their blue cards, putting them into the outstretched hand of the crew member.

All this talk about blue cards was not going to win him friends here.

He passed Shadow six blue cards, each with a date and time written on it in Hinzelmann’s old-fashioned handwriting, then entered the details of each in his notebook.

He passed Shadow six blue cards, each with a date and time written on it in Hinzelmann's old-fashioned handwriting, then entered the details of each in his notebook.