When I flew air taxi on a PA31, we wore overalls for exactly that reason! (95% of our contracts were cargo)
I fail to see the need to wear uniform to instill a sense of identity and discipline into an FTO - utter b*llocks. You're taught to conform and be a well disciplined individual at school not an FTO who are taking 60K off you. OAT is not Eaton for god's sakes! Hmm..but then maybe it is....
Save the uniforms for the professional boys who are required to wear them and have earned them. If you want to wear something because you have the intense desire to belong and you lack individuality, then a smart polo shirt with a small logo would suffice wouldn't it?