At my recent NEXUS interview at YYZ I noted the office was pretty empty. I arrived an hour early and was seen right away. I asked the CBSA agent whether they allowed walk-in appointments because Mrs. Xyzzy's appointment was still a few months off. To my surprise, I was told that yes -- one could walk-in for an interview without an appointment. Such a requested interview would come only after scheduled appointments. But for at least the next couple of weeks they are running at a reduced interview schedule while they ramp up after being closed for a while. So, I was told they should be able to interview her. A few days later, we headed back out to YYZ and sure enough were able to get Mrs. Xyzzy an interview without much of a wait. I hope this infrmation helps!