At many offices I have worked in I have noticed that many times when a seminar or event for staff is organized, the people who organized it don't show up.
If a function is set up at work and the managers don’t show any interest, what does that tell us about how important it is to the company and whether we listen or not? If you are a leader and are in a role of mentoring or supervising employees then you need to set the example and show up.
Leaders should be there to answer any questions and show support for what their staff are learning. It puts a stamp of approval on the event.