I’ve had dozens of jobs, all asked on the application if I was a citizen, I replied yes. They never asked for proof (citizenship papers). I think just answering “yes” as to U.S. citizenship may put the onus on the applicant, instead of the employer. Wonder if that would hold up in court?
If an Employer is not requiring the use of the I-9 form, for any employee, they are not following the law.
The I-9 makes an employee’s answers the same as a legal sworn affidavit, with a federal charge of perjury possible if the individual lies on the form or commits fraud in the manner of producing a phony document with the submission of the form.
If any of your previous employers did not require employees complete the I-9 form, they have not been legally validating that all employees can legally be hired. If there were/is ever any question regarding any one of their employees, and they were found to not have completed I-9 forms for all their employees, they could be subject to a legal complaint beyond any matter relative to a single illegal hire.