Stability of the event horizon in (2+1)-dimensional black holes

Three gedanken experiments constructed to test the cosmic censorship and the generalized second law of thermodynamics by attempting to exceed the extremality conditions of (2+1)-dimensional charged or rotating black holes are presented. These experiments correspond to the addition of matter with a negative gravitational energy, or an infalling classical charge, or a rotating shell to charged and rotating black holes, respectively. Even though the reasons for obstructing their falling into the black hole are different, we arrive at the same conclusions that the event horizon of a (2+1)-dimensional black hole is stable, and that the cosmic censorship and the generalized second law of thermodynamics are well protected.