Note that, without a consistent theory of quantum gravity, we don't know if black holes of such sizes can actually exist; and unless we happen to detect some, we don't actually know if Hawking radiation exists - it's not something that can be observed for a stellar-mass black hole in realistic time frames (a stellar mass black hole is predicted by the theory to evaporate after ~10^64 years - so the evaporation is far too slow to be observable; further, in the current age of the universe, the temperature of the cosmic microwave background is too high compared to the temperature of the Hawking radiation emitted by a stellar mass black hole for it to be observable, even theoretically).