An 18-year-old German pilot landed in Russia's Red Square without permission. It helped bring an end to the Cold War!

de bene esse: literally, of well-being, morally acceptable but subject to future validation or exception 

In 1987, Mathias Rust, a German aviator, decided to relieve the tension created by the Cold War. He wanted to create a "bridge" to the east. In this case, "the east" was Russia. In May 1987, Rust, an amateur pilot, took off in Finland and flew his plane to Red Square in Moscow.
He was tracked by Soviet Air Defense during his flight, but they never received permission to shoot him down. The Soviet air defense system was supposedly impregnable. Rust openly disproved this, and his flight's success led to the firing of a number of Soviet senior officers.
This breach of security helped Soviet leader Mikhail Gorbachev implement reforms that helped bring about an end to the Cold War. So perhaps Rust's mission was successful?