How is it that if I am late to my appointment with my physician, I don't get to see him? Or my dentist, if I'm late there, they give the time to someone else and I get my hand slapped for being late? If I'm chronically late for work, guess what - I can get fired.
You would think with all this incentive for the general populace to be on time, that showing up for something of significance would have people motivated to be on time? For example, let's say that you've gotten an invitation to the swearing in of your Member of Legislative Assembly. The invitation says that the event is scheduled to start at 11:00 am. The Lieutenant Governor of the Province will be in attendance - you may have heard of him, he's the Queen's Representative to the Province? Nice fellow, but I'm sure he's a busy guy and has better things to do than sit around waiting for the spectators to be seated in the gallery of the Provincial Legislature.
So, in good timely fashion, Mrs. Spit and I showed up ahead of the 11:00 am start time. We were seated and sat waiting for things to begin. Of course, you can't have things start until everyone is there... including the spectators I suppose. So we pass 11:05, still people filing into the chamber. 11:10 - we still have people straggling into their seats - good thing we haven't started yet. 11:15 - you have to be kidding, people are STILL making their way to their seats!!!!
In my not so humble opinion, if a timing is presented as the time that things start - then that is the time that people should be at the venue, ready for action. Fashionably late you say? Frickin' rude I say! It's really not hard to show up on time, trust me, it's not. I mean, if they said "the marathon starts at 11:00 am" you're not going to see participants showing up at 11:15, right? Why? Oh, because there's a starting gun!
In my world, people would be on time. They would be considerate for the time and effort that went into planning an event such that the event was ready to go for the start time. Arriving early would be smiled upon. For the cretins that are late? Sorry, we started 5 minutes ago, you're not welcome. I'm not kidding. Lock the doors and shut them out. Or start the car and leave without them. Show up late to class? Guess you miss the information being taught that day. If you can't be bothered to show up on time, why should I be bothered to be considerate back to you?
Sure, there is the other extreme - showing up waaaaay too early. That's a waste of time as well. I should know, I've had people demand it of me in my past, and it just pissed me off to be ready to go, 1/2 hour ahead of the "be ready to go time" and then be forced to literally stand around for that 1/2 hour.
All I ask is that people show up when they are asked to. Things will go as planned and everyone will be happy. If you're an attention hog, well, time for roast pork to be served, because I'm sick and tired of the rude boars of the world.