At the subatomic scale, there is a constant background "static" of random quantum fluctuations producing particles. On the larger atomic and macro scale, the random particle-antiparticle pairs cancel each other out.
The existence of this background quantum energy sea that permeates space-time has been proven by direct observation. Namely in the Casimir effect, but it also creates detectable noise in certain other very sensitive scientific insturments and has to be taken into account when taking measurments.
The reason smaller quantum black holes give off Hawking radiation faster, and evaporate faster is that the event horizon of a black hole cuts apart the neutral potential of the quantum particle antiparticle pairs, and the smaller the black hole, the smaller the Event Horizon is, and the smaller it is, the more of these quantum fluctuations it cuts through producing "real" particles. General and Special relativity does not allow for violations of conservation of mass-energy E=mc^2. So the black hole has to lose some mass in the transaction. And the now real energy expresses itself as efficiently as possible, which means it produces a high-frequency gamma photon.
Even with the new findings, getting one of these black holes to grow is nearly impossible. It still only has an overall gravitational pull of it's mass which is less than an atom's. It's only real dangerous attribute is the gravitational gradient is still incredibly deep, but another particle has to touch the event horizon to get "eaten". And at that scale you're dealing with quantum motion, tunneling, uncertaintly etc. it's not a bunch of Newtonian billiard-balls in which we use to try and visualize these phenomena.
And it's only "nearly" impossible in a mathematical sense. In real human timescales it is effectively impossible. Running the LHC at full tilt until the sun burns out. On a more human-scale analogy, it's kind of like having a slippery little guppy that swims at Mach6, and if you don't somehow stuff a whole watermellon in it's mouth every second, it'll die.
Well, now the physicists have come back and said. "Well, now maybe you've got ten seconds to feed that guppy a watermellon."
And Hawking radiation in nature isn't very observable in practical terms, because the large black holes in space that we can find, the x-rays and other EM of the infalling matter would overwhelm it, and as we've discussed, the big ones give off less Hawking radiation. And IF there are any "natural" quantum black holes, their overall gravity well is infestimal, so it's not pulling in any matter to tell us to give off the signs that "There be a black hole here". etc.
