This has been addressed in fictional plots for ages. How well do you know the person you're talking to? There should be something only the two of you could possibly know. In Rick and Morty, Morty tells a judge the last words her husband spoke to her before dying to convince her he was really communicating with her dead husband (which was actually not true, but his tech was way beyond anything real AI will ever be able to do). Some digital cloning company like this might get your face and the basic shape of your body, but what about scars usually covered by clothing? Genitalia if you're willing to go there?

If it's a person you don't know, first ask if it matters. Is the point to get information or talk to a real person? If it's prospective romance or something, real people can still catfish and otherwise scam you. If, for whatever reason, it really matters, ask them to do a bunch of athletic tasks. Handstand. Broad jump. Throw a ball across the room. They're probably not going to scan people they digitally clone to see how they do these things, so chances are good with the techniques that exist today the vast majority of training data will be from elite athletes doing these things on television. No real person would actually be good at all tasks and will either be totally unable to do some of them or can do them but very clunkily. Do they warm up? Chances are good training data won't show that and AI clones trained by ML might not bother, but a real person would have to.