Rust's landing was actually a huge black eye to Soviet military and intelligence. From what I recall, their radar techs reported the contact but the chain of command fell to pieces, especially between handoffs.
His plane has been intercepted and identified as a Yak-12, at which point the military erroneously redesignated him as a flight rules violator as opposed to cross-border intruder.
A slightly different situation, but within the general "the eagle doesn't catch flies" pattern.
The military are concerned with somewhat different threats than a rusty barrel or cocaine.
I wonder if any drug people ever thought of small unmanned solar-powered boats - these could be even stealthier.