Proposed ProGuard keep rules are extremely broad (== bad)

The article mentions "the most basic example of ensuring your library classes are exported" as including

```
-keep public class * {
public protected *;
}
```

... these are very imprecise keep rules which will undermine the effectiveness of ProGuard across the rest of any app that includes this library. Even presenting the rules here as a viable option may be doing harm for library developers and the consumers of those libraries.