I don't believe you can impose disciple on people. My belief is that disciple, like aikido, is an inner journey. As an individual you are either working on being disciplined, to whatever degree, or not. I also agree that when people are late to class it is disruptive. When I have a student that is habitually late I or one of the dia-sempai speak with them about it. We want people to feel welcome and don't believe in shaming or scapegoating people. However we do hold people accountable. We stress to them the importance of being early for class and helping clean the dojo etc... We try and provide an environment where people feel safe to explore their inner dimensions, the path of aiki. It is not always easy but quite rewarding. It is not my belief that you can teach aikido but only show your feeling and lead them to it. I personally have a "thing" about being late. I can't stand when others are late or to be late myself but this is my problem. In any case people always either start showing up early or stop showing up after a few conversations on the matter.
Paul
Cape Cod Aikido Kenkyukai
http://www.aikidokenkyukai.org/usa/ma/ma.index.html