[JamesSwift]

Or they can just drop off 5 minutes before their next meeting and avoid having everyone else adapt to their preferred start time??

Even better is they only need to use that method when meetings actually run full time rather than every single meeting they are in

[crazygringo]

The problem is that final decisions tend to be made in the last 30 seconds of a meeting. If you're a manager with a stake in the outcome, you can't leave the meeting until you've ensured that the outcome works for you. Leaving 5 min early is often simply not an option. While arriving 5 minutes late is. It's not an ego thing -- it's the fact that meeting leaders often let meetings run long.