O-4 - Earth and Sun have survived about 4.5 Gyr of ultra-high-energy cosmic-ray bombardment
Directly bounds only scenarios in which cosmic-ray-produced black holes would be stopped inside Earth or the Sun (e.g. charged/EM-interacting black holes); the neutral stable case escapes and needs the WD/NS route.
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Why this is evidence
Under H-7, any cosmic-ray-produced long-lived black hole that stops in Earth or Sun (charged/EM-interacting variants) would have had 4.5 Gyr to accrete; survival disfavors those H-7 sub-cases. Under H-4 survival is certain. Neutral fast black holes escape, so the bound covers only the stopped sub-cases.