This seems as good a place as any to ask: when the particle-antiparticle pairs are made at the event horizon, one falls in, the other is emitted as radiation. Why don't the p & ap produced then pair up with and annihilate with other ap and p created in the vicinity such that it wouldn't really be detectable over ordinary vacuum activity. This could happen both inside and outside the horizon. It seems like Hawking radiation (if I've understood correctly) could be produced but would be almost impossible to detect as it would all annihilate immediately?
The particle []or[] antiparticle (only one avoids falling in) produced usually does pair up and annihilate with another (anti)particle, but that happens above the event horizon, so the photon resulting from that annihilation sometimes is pointed away from black hole and escapes. It's only very small black holes where the pair-production particles themselves have sufficient height and speed to escape.
Eventually being a really long time.