I've played both sides of this equation.

I led a competitive guild in Guild Wars for about 7 months. People that didn't show up on time for Guild vs Guild were benched until they started showing up on time. The only way around that was to post to our forums saying you would be late / out etc. I did however always grant a 15 minute immunity...if you were more than 15 minutes late, say hi to the bench for me.

In CoH/CoV I would frequently schedule Task Forces. I would always tell everyone to be ready early, because at the appointed time, if you weren't there your spot was gone. If scheduled for 8:00 PM, at 8:01 I would see if anyone wanted any of the spots open. It might seem a little harsh, but I used to typically do 2-3 Task forces a night, and this was almost a necessity so that things wouldn't get way out of schedule.

I understand real world needs, I have 3 kids...but if you're going to commit to something, commit to it, and make it happen. Show others the respect you expect to receive from them.

Anyway, just my $0.02.