I think there are insurmountable questions of personal identity inherent in your question. If you add some new knowledge to someone then it's quite feasible to claim it's the same person, because we see that around us - going on a course or reading a book or whatever. However, taking knowledge away from someone might mean they're no longer the same person. Thus, sending Carlsen back to the 1800 hundreds with no knowledge of anything that happened after that date would mean he wouldn't be Carlsen any more.
I think that sort of begs the question. Either way, the person isn't the sme person. For instance, the Morphy I know of would never apply himself in chess to the intensity of focus that modern masters do (and must do). To assume he would/could changes the very nature of the man. Trying to bring players into future realms seems as futile as trying to move modern players back in time.
he has a point. if you take Carlsen's chess knowledge away, he might become Justin Bieber.