I would also ask him if there were ever a vaccine for COVID-19. If he had an elaborate story about the discovery of a vaccine, or some other elaborate story, I’d suspect fraud. If he said “What?” Then he’s more likely to be real.
A fraud is going to expect questions about the near (to me) future, and current events, and have stories ready. Someone really from 2220 isn’t going to know much about 2020. Unless COVID-19 ends up becoming something on the scope of the Black Death, it’s unlikely people in 2220 will have heard of it. (How many people had heard of the Spanish flu before the H1N1 scare 10 years ago?) And even if COVID-19 does become the infamous plague of 2020, that is taught in history books, people from 2220 probably will not know many details, such as the name of the disease (COVID-19), anymore than people today can say Yersinia pestis, or remember things such as that it started in the Wuhan province of China, or who the US president was at the time. If he does know those things, he’s a history buff, who will know things from other eras. Someone from 2220 who knows who was the US president during the plague of 2020, will probably know things most people from 2020 don’t know, like who Queen Victoria’s two Prime Ministers were. (Disraeli & Gladstone; I’m a history buff. :p)
It’s kinda like biblical prophets. They claim to be writing at one time, but we know they were writing in another, because they have excellent knowledge of a 3-4 years period, vague knowledge of events before that period, and are wildly wrong about events after that period.
If he seems to know an awful lot about 2000-2020, is accurate, but vague about the far past, and says things about the future that change with retelling, like a criminal who is making up an alibi, that’s the biggest clue.
I would expect his clothes to look like they were mass produced, not made on a Singer in someone’s sewing room. I sew as a sort of minor hobby, and it’s easy to tell something homemade from something mass produced. What’s more, I would expect his clothes to be labeled in some way. Maybe clothes cleaning is by some entirely different process in 200 years, but I would still think clothes would have some kind of care labels. This is 200 years, not 2000 years. Maybe he has an implanted computer device that reads a label I can’t see, but he can still show it to me somehow.
Further, I would expect that if his clothes are not cotton, linen or wool, then whatever polymer they are made from is fire resistant in 200 years, because this is a technology that is always being improved upon. If he has clothes that are especially resistant to inflaming (even if they discolor from flame, or something), this would impress me.
Anyway, I have a lot of confidence in my ability to detect a costume, even a really well-disguised one.
I would ask about recent (to him) inventions, and want to know what they are called. If he makes up nonsense words for them, he’s probably a fraud. That’s not how neologisms are fabricated (unless they are borrowed from literature, like referring to outsiders from your profession as “muggles,” or dwarf animals an “munchkins*”), but it’s what 3rd rate sci-fi writers do. Real neologisms are either fabricated from Greek and Latin (microwave oven), derived from existing words (software), or loan words form other languages (karaoke). And this has been true for the history of the English language.
*Yes, I’m aware that Munchkins being small is a fabrication of Hollywood, and does now go back to Baum.
