I expect that when this gets to court the Administration* will argue just that, pointing to the cell phones that they've handed out to the illegal migrants they've released so the migrants can call to arrange hearings, and claiming that those cell phones represent detention. I suspect the judges' response will be something along the line of "Do you think I'm stupid?"
Police do indeed have discretion whether to issue tickets. But while I can't speak for all fifty states (this
is the US, after all), I believe that in general that discretion is explicitly given to them by state laws. Certainly that is the case in Massachusetts, as illustrated there
in 2003 when the police union sued the Newton chief of police, arguing that the law granted that right to the police officer on the spot rather than the chief of police. Here's the wording in Massachusetts law that the case was over: “If a police officer observes ... a civil motor vehicle infraction, the officer may issue a written warning or may cite the violator for a civil motor vehicle infraction.... If the officer issues a citation solely for one or more civil motor vehicle infractions without any associated criminal violations, the officer shall indicate on the citation the scheduled assessment for each civil motor vehicle infraction alleged.” Note the language of that law--an officer
may issue a written warning or
may cite the violator (discretion granted), but if the officer issues a citation that officer
shall indicate on the citation the scheduled assessment (discretion
not granted). So I'll ask again, where in immigration law is similar discretion granted to the executive branch?
And another thing, that lawsuit? The police union won, the court ruled that the legislature had deliberately shifted the responsibility for making the decision to issue citations from the chief of police to the individual officers on the spot. So how about "prosecutorial diescretion"? Doesn't that by definition lie with the
prosecutor rather than their superiors, and certainly not with a cabinet level officer or the president?