The "pass system" was an informal and unevenly applied control mechanism imposed on the Native peoples on the Prairies from 1885 until the 1930s. Under it, Natives could leave their reserve only if they had a written pass from their local Indian agent, authorization that was frequently granted only after consultation with the local reserve farm instructor. The system arose from fears in the early 1880s of a pan-Indian movement on the Prairies focused on treaty revision; the events of the 1885 Rebellion only compounded these fears. The goal was to prevent interaction among Natives by restricting off-reserve movement, thus inhibiting political protest. There was no legislative basis for the practice, and it was never part of the Indian Act. In 1892, the Canadian government was cautioned that the pass system was illegal, so the N-WMP stopped enforcing it. The practice lingered, however, and was expanded from the narrow purpose of impeding political activism to controlling parents who wanted to visit their children in off-reserve residential schools and to obstructing participation in frowned-upon or banned cultural activities held elsewhere. The pass system was not always effective in itself because of its tenuous legal foundation, but agents could use a coercive ration policy to force compliance. Although applied sporadically and with varying degrees of effectiveness, the system was still in use in some regions of the West until the mid-1930s.