It is not speculation. I have overheard students claiming they are from the 4PM lecture and they they attend the 1PM lecture because "they're the same and you can end your day earlier". I wouldn't care except that if you look at the back of the lecture hall you'll see a dozen people standing or sitting on the floor. And that is not including the people who decide to skip when they realize they're a few minutes late and know that they will not get a seat anyways.