"...Are HP at all capable of any kind of due diligence?"
No! it would seem to be part of the culture, see this link: http://www.theregister.co.uk/2003/08/14/hp_recovers_1_8m/ (source: linked in the comments of the ARSTechnica article Justicesays references in their comment here).
Reading between the lines of the 2003 article, it would seem that even having determined the order was fraudulent, HP still shipped kit, invoiced, received payment and then claimed they had been had!
LOL...it was a rhetorical question!