I attended a master class by a well known yoga instructor. I overheard how awesome he was at a conference in San Francisco and was delighted to find out he was coming to our town. The day of the master class I left the house extra early to make it to the west side of town in rush hour traffic in time for the "show". I arrived almost an hour before the scheduled start. The room was abuzz; yogis were talking excitedly and stretching on their mats with their noses on their knees and toes pointing to heaven. I enjoyed meeting the other yoga instructors and students at the session. The starting time came and went and the "famous" instructor was nowhere to be found. We received an update on their status - they had landed and were on their way in rush hour traffic. (They mentioned the instructor had another workshop that day and was coming directly from that - it appeared to be a case of poor scheduling). The instructor was laid back about his arrival when he finally did make it. After an hour and a half of lecture we finally started to move for the master class but I was already very disappointed.
I think some people just let it go because this was a famous person that they worshiped. But for me it was a small thing that told a lot about him.
Your audience looks forward to you. Many times they spend money, rearrange their schedules and make every effort to be there at the start for you. You should give them the same consideration.
I know. Sometimes unpredictable circumstances cause us to be late and that is understandable. I have given myself double the time to get to a speaking engagement only to find myself at a standstill in traffic because of an accident that closed the freeway and I should have given myself triple the time - who knew?! But those times are few and far between. Just not planning enough time to get there tells your audience they are not worth your time. What message are you sending?