AFAIK Hawking radiation has never been detected. It is hypothesized on the basis of current theories of quantum mechanics and gravity, and those assumptions imp

AFAIK Hawking radiation has never been detected. It is hypothesized on the basis of current theories of quantum mechanics and gravity, and those assumptions imply a thermal distribution of energy. So, we have a reason to think that Hawking radiation occurs and has this property, while no-one so far has proposed a mechanism that would encode data on it.