Inspection and Entry at a Port of Entry: Where is There an Admission? (Jan. 30, 2013) (this applies beyond the DACA context and discusses entries in three common situations: where a noncitizen is waved through a port of entry with no questions asked; where entry is gained by fraud or misrepresentation; and where there is a false claim to U.S. citizenship).
http://www.legalactioncenter.org/practice-advisories/%E2%80%9Cbrief-casu...