So after a week of comments and research, it’s time to answer the question.
This is a unique problem. Mainly because of some of the procedures at Bromont. During glider ops you are not to overfly the airport.
So that rules out joining the mid downwind after overflying the airport. Because there was no traffic advisory available, then the control zone was an ATF. Which means there is only one other way to join the circuit, that is via the straight-in downwind.
I think this is a knowledge gap during the training process. I’ve come up with a chart that will help with figuring out when MF and ATF rules and procedures are in place. Please let me know if you find any errors so that I can correct.
Comments are welcome.