Why on earth would a competent F/O be worried about doing his job?
A qualified pilot needs to be at the controls. I couldn't care less if he is Training Captain, Captain, SFO, FO or SO. As long as he has passed a recognised training course he or she should be perfectly competent to fly he aeroplane on his own with the wing on fire & hydraulics shot to bits. Normal day to day Ops should be a piece of cake.
GA
ps. perfectly reasonable question IMHO.