I too was taken aback by lobaeux's comments, but he is definitely not a troll. I think his logic was somewhat clouded by his experience working for an airline with one type of aircraft. He probably didn't realize that this is quite common. It's been happening at American on the 190 for years.

Additionally, in the military this has been the case forever on the fighter side. A Lt. with 200 hours of student time and 20 hours of Introduction to Fighter Fundementals (IFF) is the Aircraft Commander (PIC) of a Fighter he's never flown, right off the bat. There isn't even such a thing as SIC in a fighter.