Was there a NEC Code Change that disallows 14 gauge wire in a residential receptacle?
To my knowledge the only recent changes dealing with residential receptacles, says that they must now be tamper resistant, and that ALL garage receptacles must be GFCI protected. There were also some changes dealing with Arc Fault breakers in NEC 2011, but I haven't read through it all yet.

Code compliance can be a fickle bitch, and the minimum code applicable for your area will depend on what your local government has chosen to follow.  To my knowledge, there have been no changes that say you cannot use #14 for 15Amp receptacles.  But even if there were changes, say for example in NEC 2011.  Your area may still follow NEC 2008, or even NEC 2005, in which case those are the minimum standards you must follow.

The best way to know for sure, is to contact your local government to determine which standard they follow.  Then do some research into that standard.  Or contact a local licensed electrician, and ask.

So if I were you I would ask my friend to site some section numbers (then look them up if he actually can), or call a local master electrician.