And where would they have gotten this impression? Do you think that mothers send their unaccompanied kids to the borders based on day to day banter, do you think that south american mothers are so stupid they just mishear a rumour and forfeit their kids based on it?
They don't have to be stupid to misunderstand the provisions of the DACA (assuming they have access to those), but couple that misunderstanding with local fears and desperation and some percentage of mothers will. And some kids are going to try anyway, for family's sake.
"Individuals who request deferred action must have:
Been under the age of 31 on June 15, 2012
Arrived to the United States before reaching their 16th birthday
Continuously resided in the United States from June 15, 2007 (last five years) to the present
Been physically present in the United States on June 15, 2012, as well as at the time of requesting deferred action from USCIS;
Entered without inspection before June 15, 2012, or had any lawful immigration status expired on or before June 15, 2012
Been in school at the time of application, or have already graduated or obtained a certificate of completion from high school, or have obtained a general education development (GED) certificate, or are an honorably discharged veteran of the U.S. Coast Guard or the U.S. Armed Forces
Not been convicted of a felony, significant misdemeanor, or three or more other misdemeanors, and do not otherwise pose a threat to national security or public safety"