Forum: Ruby on Rails Rails Guide:"For belongs_to associations, has_many inverse associations are ignored." not clear?

Perhaps I'm bing a bit thick and missing something obvious (possible), 
but
I found the caveats listed in section 3.5 of the Associations Rails 
Guide<http://guides.rubyonrails.org/association_basics.html> badly
worded and confusing.

The section gives an example with a has_many <-> belongs_to relationship 
is
setup with inverse associations on both side, but then states the 
caveat*"For belongs_to associations, has_many inverse associations are 
ignored."
*

Could someone actually explain what that means in concrete terms? The
example and the caveat appear to be contradictory. If the caveat is 
correct
then I'm not sure I understand how the example works.

Paul

On Mon, Nov 12, 2012 at 4:09 AM, Paul Leader <paul@paulleader.co.uk> 
wrote:
> then I'm not sure I understand how the example works.
I've never needed :inverse_of.  Looks like academic masturbation to me.


--
Greg Donald

It is useful in a small number of situations, mostly where you need to
ensure that two different references to the same object actually refer 
to
the same instance.  I've only needed to use it twice, both times were 
where
we have callbacks updating multiple related objects based on data held 
in
each other.

Anyway, if anyone else does understand what that caveat actually means 
I'd
appreciate an explanation.