[Wikipedia](http://en.wikipedia.org/wiki/Spanish_prepositions#Compound_prepositions) mentions that _para con_ is rarely used, but I hear it often enough to warrant this question.

On the other hand, the Wikipedia article references the [Diccionario panhispánico de dudas](http://buscon.rae.es/dpdI/SrvltGUIBusDPD?lema=A) with respect to the use of _a por_ and _por_.

When is the compound preposition _para con_ preferable to just using _con_?