At least one OSCO Deputy, Tony Rusciano, was willing to risk and lose his job vs. exposing communication with Casey. And Casey certainly had plenty in her circle that had/have connections within local LE.
So, if Casey needed a plate look-up after she set her sights on ZFG, she likely had someone she could turn to for help to run D.A.V.I.D. or other query to get the essential info.
Does D.A.V.I.D. keep a log on queries? Queries on ZFG plates ~6/17 would be telling.