For a non-extremal Kerr–Newman black hole satisfying M^2>a^2+Q^2, small electromagnetic (or gravitational) perturbations do not destroy the event horizon or violate the inequality; instead, they excite quasi-normal modes that decay in time, and the spacetime relaxes to a nearby Kerr–Newman solution with slightly shifted M,a,Q. Superradiance can amplify some modes, but in asymptotically flat spacetime this energy escapes to infinity, so no true instability develops. Only in special or extremal cases does the behavior become subtle, but under realistic small perturbations the horizon remains stable.