Upon reading the full article quoted, I think the mentioned pilot mugging may well be what the couple I met in Puerto Madero referred to.

Much of the article focuses on places that I would regard as far more dangerous. Indeed, I recently met a lovely couple (one from Denmark, the other from Venezuela) who moved to Buenos Aires from Caracas because they woke up one night to armed robbers in their house in Caracas. For now, anyway, they are not expecting that would happen to them here in Buenos Aires.