I mean, it’s possible but unless he specifically said that he wouldn’t use his identity during the experiment, just proving who he was would be enough to trivialize the risk of even a significant loan for most people. A lender would know that whatever happens, either they’ll get paid back by him from within the experiment or he’ll pay them back as the billionaire after the experiment, maybe even rounding up to the next significant digit or something crazy like that (but still trivial for him).

Also, “I was doing an experiment” isn’t a defense against fraud. Though him being a billionaire probably means that the only penalty would be paying back the victim with maybe a little extra plus legal fees or hush money.