It also depends how it is worn. As TTN said, some are clearly Walts. Some re-reactors are both realistic and credible, other ludicrous. I saw a MRAF in the wrong jacket and modern rank ribbon.
As Tartare said, he wears a selection of badges in the wrong place.
The problem arises when one is credible and in the right place. When you talk to them though you soon find they are fake.