With all due respect, Miranda only applies to Custodial interrogation. The blurb talks about refusing to speak with police prior to arrest which implies a non-custodial interaction where officers are not required to make a Miranda advisement.
Since Miranda is well-settled, and prosecutors cannot comment on someone's silence once they are in custody, the implication here is that some prosecutor is attempting to test the limits of 'silence' and it's intersection with a police investigation.
The theory probably being that if one is innocent they would answer questions posed by police in a non-custodial encounter. (I personally believe that absent a law to the affirmative, one has no obligation to speak to police and case law bears this out...IOW, there is case law that states in a non-custodial encounter police have zero recourse if someone refuses to answer their questions and simply walks away.)
I would hope that SCOTUS would clarify and expand Miranda to the point that a police officer would be required to inform someone that their encounter is clearly non-custodial and that the person is free to leave at any time without answering any questions that the officer puts to the individual and that prosecutors cannot comment on such an interaction during a trial.
But I won't hold my breath.
More generally, I would suggest that any "consent" citizens give to cops in such situations shall be presumed coerced, absent clear evidence to the contrary (and citizens have the right to have questions of coercion decided by a jury that would be informed that if they find that evidence was obtained through coercion they should not construe it against a defendant).