lol
My shell always enters exactly on time. 7:15pm EDT on Thursdays and 7:30pm EDT on Sundays.
The only time I've ever not entered the zone that I posted on the Calendar was last Thursday when my shell was scheduled to enter Dynamis - Windurst and was unable to due to Burnout's shell (ADisturbingCreation/Disorder/etc.) entered before us as we were waiting until our start time.
As for the 'taking other zones', we have NEVER entered a zone ahead of another LS that was scheduled on the Dynamis Calendar.
Going /away is bad when you're trying to lead something? Gee, must have missed that. It's not uncommon for me to go afk when I want to avoid distractions.
And disrespectful? Hardly. I have received very rude messages from people that think their zone was 'stolen' when they refuse to post on the calendar and I always respond in a civil manner.
If you don't want to post your schedule on the calendar with the other LS's, that's fine. But like I've said before, doing so forfeits any right you may have had to *** and moan about not being able to enter the zone you want to, not that it stops you anyway.