Should this line not be removed and let `blank?` just fall back to it's [default implementation in Object](http://api.rubyonrails.org/classes/Object.html#method-i-blank-3F) i.e.:

```ruby
def blank?
  respond_to?(:empty?) ? empty? : !self
end
```

That way `blank?` and `present?` etc. won't give errors if the collection is `nil` and will still use the optimized sql of `empty?` in case of an activerecord object.