The Department of Homeland Security makes the determination on employment eligibility; all employers are required to complete an I-9, Employment Eligibility Verification. The I-9 form has a section the employee must complete: "I attest, under penalty of perjury, that I am (check one of the following):
A citizen or national of the Unvieted States
A lawful permanent resident (Alien#) A-_____________
An alien authorized to work until ____________(Alien # or Admission #______________)
I don't see how an I-94 without an authorization stamp could be used by an employer for verification purposes, since it wouldn't specifically state that authorization.
Also, from the USCIS "How Do I..." Factsheet
page:
How Do I Get A Work Permit (Employment Authorization Document - EAD)?"Who is Eligible?
* The specific categories that require an Employment Authorization Document include (but are not limited to) asylees and asylum seekers; refugees; students seeking particular types of employment; applicants to adjust to permanent residence status; people in or applying for temporary protected status;
fiancés of American citizens; and dependents of foreign government officials. Please see Form I-765 (Application for Employment Authorization) for a complete list of the categories of people who must apply for an Employment Authorization Document to be able to work in the United States."
I would not be permitted to complete hiring paperwork for someone who didn't present an employment authorization document when completing their I-9 (speaking from a university research department standpoint).