Answer: Here is the exact legal language on identification at the LEA level:
“Each local educational agency liaison for homeless children and youths, designated under paragraph (1)(J)(ii), shall ensure that–
(i) homeless children and youths are identified by school personnel through outreach and coordination activities with other entities and agencies;”
42 USC §11432(g)(6)(A)(i).
In addition legally, you must provide support to school staff to ensure they do identification and referrals appropriately:
“Each local educational agency liaison for homeless children and youths, designated under paragraph (1)(J)(ii), shall ensure that—…
(ix) school personnel providing services under this subtitle receive professional development and other support”
42 USC §11432(g)(6)(A)(x).
Legally, the liaison has both the authority and the responsibility to identify McKinney-Vento students and ensure their immediate enrollment, access to school of origin, and other rights/services. Other school staff can make those determinations only to the extent you have delegated that authority to them. And legally, your district is responsible for ensuring the identification of homeless students.