My absolute favourite is when the examples say something like "production code should not be written like this, this is just for clarity" with no indication of what's wrong with the code.
Is it just normal Rust stuff like there's unwraps everywhere and it's one big file? Does the example have security or performance problems? Is the example unidiomatic or over-verbose or is it ignoring features real-world code would use? EXPLAIN YOURSELF!
I personally prefer the straight forward everything in one file examples. The worst examples are those that come with its own ad hoc example framework I first need to understand before I can understand the example.
It's probably to encourage people to underdtsnd the example properly then write their own code. Too many people copy/paste examples without understanding them completely.