That all makes sense. I'm not sure why you hope the others won't walk, though. That's a somewhat negative way of looking at it.

I don't think you have to go to a very big school to have that same experience. Mine has about 5500 undergraduates, and they run the school-wide ceremony the same way. They announce your department, you stand up, people clap, you sit down. That's not really the reason you go to those things. The reason is more for what you said you didn't have, though, which is a sense of moving on with the people you got to know over the past 4 years. Granted, I don't know 98% of my class, but I got to sit with 4 of the people I did know so we had fun. Plus, our speaker was Queen Noor of Jordan, we gave an honorary doctorate to her and civil rights leader (and Representative) John Lewis, and our previous chancelor Margaret Thatcher showed up. So, hearing these incredible people speak is a nice thing.

Anyway, despite the fact that they tell you you have graduated at that main ceremony, I definitely considered the smaller ceremonies for your departments the real thing. I was in a department with only 13 graduates, 10 of whom were there instead of at their other department (for double majors). It was nice to have an intimate send-off.

Regardless, I'm merely congratulating people for earning their degrees. Whether you're going to use it or not, you probably had to work pretty hard at it.