Playing this out in my mind, exactly how early in the process would they assume said person would stop having a right to delete their phone data? Suppose I am

Playing this out in my mind, exactly how early in the process would they assume said person would stop having a right to delete their phone data? Suppose I am in the car, and am told to wait in the car while such-and-such? Or suppose I do so after being instructed to get out, but before doing so, so I am within my car's property and/or not yet detained or in custody? There's going to be a lot of legal questions in this case about where the line should be re-set or re-drawn. And it's also all stupid and in violation of the Fifth Amendment, at least IMO.