Back when people got physical checks for payroll, I worked at a company that did this, and gave physical stubs to those of use who did direct deposit which was still kind of new.

Biweekly, the person handing them out would take them home to sort by floor/area/whatever to ease their work the next day.

You guessed it, one day their car was stolen, with ALL of our checks/stubs in them. And our SSN's were printed on them too.

We were given a year of credit monitoring at the credit unions, paid for by the company. And they stopped printing the SSN's on them.

Could you please share some online references or sources for this?

"It was never made public" - do you mean to imply that this is otherwise unverifiable