Every time somebody got lazy and used "unsafe" in Rust that's unavoidably annotated in the code. If the compiler can't prove it's safe and you don't label it "unsafe" it won't compile at all.

Even coming in years later, a maintenance programmer can identify this code is suspect, whereas these other parts are safe.

Whereas if you get lazy in C++ you can do whatever unsafe things you want, anywhere, and it leaves no trace.