Sharing my experience for OCI Walk-in Application at the Brampton location.
Arrived at the location at around 6.25am and there were around 18 people ahead of me, the first person in line had queued up at 5am in the morning. Doors opened at 8am and around 8 to 10 walk-in applicants were given tokens and were asked to wait inside. It seems that between 8am to 9am there aren't any appointments so they let in walk in applicants until the appointment candidates start to show up.
At around 8.20 I was given the token. Lady at counter 9 asked for the checklist and documents, as far as the original documents goes, we were only asked for the Indian Passport and all the documents were validated against the Indian passport.
At the end she asked for the photographs and pointed that the shoulders are not visible, I showed her the sample format that is available on their website where the specifications and sample images where similar to what we had. She refused saying that the shoulder should be visible, she will submit the application with these pics however there is a possibility that it will be rejected.
Since I drove all the way from East end, I was in no mood to start this process all over again so I opted for the Photo service and paid $15 for two copies of 2x2 photos, gave the copies to the lady while share arranged for the OCI drop service. In total I paid approximately around $100 for two applicants. (Photo + Courier + Admin charges). I was out by around 8.50 am.
Thanks to this community for the guidance and help in getting this through in my first attempt. Cheers!