During the 1960s in the USA a number of draft age JWs joined the Pioneer ranks. This satisfied the Selective Service officials and the Pioneers were granted Clergy status and exempt from the draft. One could also marry, get wife pregnant and get the father with dependent children deferment.
When the US abolished the draft and went to an all volunteer Military, young JW men began to avoid Pioneer service. In fact I remember an elders meeting where the CO said he hoped the government would reimpose the draft, that way there would be incentive for JW young men would join the Pioneer ranks.