My previous airline required the Commander to sign in the Tech Log to accept the aeroplane. The wording above the signature stated 'I accept that there is sufficient fuel and oil on board for the purpose of the intended flight.'
Where I work now, there is no such acceptance signature required but I have never had a call from Management asking me to justify extra fuel. The responsible attitude adopted by the company means, in turn, that I think long and hard before loading any extra fuel - but if I feel I need it, I load it. The only league tables I am interested in are related to sports not fuel burn.