Love in the Office:
People being late can have a serious effect on timetables, and on the perceived sense of respect people have for each other. If someone is late for a meeting, the others in the meeting might think it´s because that person does not respect them enough to show up on time.
If the meeting is during a work day, make sure that everyone has tools to help remind them of meetings. There are enough PC packages out there that beep and flash when meetings are imminent to make this easy. Do not berate someone for being absent-minded ... give them a tool to help fix the problem.
If these are early morning meetings, reevaluate if they really must start that early. Some people are simply not morning people, and might sleep through alarms without meaning to. Consider these issues and look into scheduling the meeting an hour later, or in the afternoon. The slight hassle of rearranging meeting times will be more than made up in more coherent discussion and better morale.
Love in the Office >