I arrived to Toronto using an eTA (I come from a visa exempt country) before my study permit was issued. After a long story in the borders office at the airport, I was given a TRV until mid September and I would have to work things out by then. They also told me I would have to pass the Canadian borders and come back in order to activate my study permit after receiving the correspondence letter. 2 days later my permit gets approved so I found out that what I have to do is called flagpoling.
It turned out that flagpoling is a thing that people do in order to get their papers done faster. After reading a lot of Niagara flagpoling experiences from people pursuing a faster procedure, it occured many times that border officers denied service after a certain number of people per day (on a first come first serve policy).
tl;dr If I have no other way than crossing the borders to activate the study permit, is there still a chance that I will get denied of service? Also should I just visit the bridge the earlier I can or just any of the working times (8am-midnight) should do?
edit Consulate people were more ignorant than me (or acted like this) so here I am again. Just bumping the post because everywhere I go to ask they tell me they just don't know.