You could get deferral as a minister or employee of a religous organization, as a student, and for various other reasons. If you had no grounds for deferral but claimed CO status, they could order you to do alternative service of some kind. You could also contrive to get rejected on the basis of certain Victorian biases which informed the miolitary in those years, such as being a flaming gay.If you refused to cooperate in any way due to absolute religio-philosophical conviction you could be sent to prison; this was more often the case in WWII, when the moral lines were much starker and the Peace generation had not started swarming the barricades with daisies in their mouths, or whatever.
A lot of our generation, facing military duty in Vietnam, decided they would not playt the game at all, on moral grounds, and moved to your side of the Falls, as you know.
A