Now the thing is, Luigi when informed that he was under some sort of "official investigation" and that Detwiler believed he used a fake name Luigi promptly and immediately gave his real name.
Luigi later explained that he was homeless and simply provided a what ID he had, which was fake.
Why the interaction didn't end with Luigi simply being allowed to leave McD's (possibly minus a fake ID) legal experts aren't sure.
That is until we read about the Supreme Court case Detwiler lost...