Let's not add strict rule for this. A good code style should be easy to follow. So it shouldn't contain too many rules, especially for things like this.

A general rule is to make the code easy to read/understand/maintain.

My habit (not rule) about the usage of `if..else..` is:

~~~php
{ // case 1:
    if (...) {
       ... very short code here...
       return false;
    }
    ...very long code here...
    return false;
}

{ // case 2:
    if (...) {
       ... very short code here...
       return true;
    } else {
       ... very short code here...
       return false;
    }
}

{ // case 3: both are very long - refactor them to make them short.
}
~~~