Not sure if you're being sarcastic here or not. Many airlines (including Delta) use 2 F/O's and 1 CA for a 3 man-crew. Flights over 12 hrs are double-crewed (2 CA's and 2 FO's.) Nothing inherently unsafe about 2 F/O's in the flight deck at cruise. We are fully qualified and typed and have gone through the same training as CA's. The only difference is seniority numbers and, of course, pay rates.
Not being sarcastic. At one airline they are NOT "fully qualified" in a captain upgrade course, nor are they subject to additional evals or any required line checks, as captains are. They are FOs who got a type-rated 15 years ago.
Here's the test. When the FO/IRO upgrades to the left seat do they have to go to a captain upgrade course? Yes? Why? If they're qualified to fly as a captain then when they're awarded captain then they should be able to simply put on 4 stripes and report to work the next day as a captain. No? Then the airline shouldn't pass them off as captains and the FAA shouldn't allow it.