In my cash game, we have a set buy-in amount and a minimum cash out time. I know, I know... I'll catch some flack for this, but I'll defend it until my dying breath. The structure of my game is derived from the preferences of the group (fourteen strong). I'm constantly running ideas by them to make the game as cozy as possible. We're all friends, so I don't want anyone to stop coming to the game because of something I unilaterally decided. Everyone has a stake, so to speak.
The set buy-in amount comes from the players preferring to start out with the same amount in chips. They know that if there's a min/max range, the more aggressive players (ahem, me) will buy in for the max and try to bully. We regularly play 25c/25c, $30 buy-in, with 25c/50c, $50 buy-in sprinkled once or twice during the calendar year for kicks. There's no rebuying up to a certain % of the largest stack because I don't want to deal with that hassle. Rebuys are up to the original buy-in amount. All of the players either voted for this structure or had no preference. It's worked flawlessly for us for three years and running.
As for the minimum cash out time, not only is it to prevent the hit-n-run (not that I think anyone in my group would do it, but you never know), but it also guarantees a nice evening. There's nothing worse than to start with eight players but then drop to five after an hour. The action would be crippled, the players would begin to lose interest, they may not want to come back for future games, etc. For the host (me), setting up the game wouldn't be worth the work if it fell to four to five-handed after a short while. Sure, you can not invite them back if they bounced early, but it's hard enough to find players (amirite?). We're coming together to have fun (first) playing poker (second). I want my guests to have fun as long as possible, so I try to ensure a minimum amount of time for that. This has also worked flawlessly with zero complaints (even from the weekly casino reg who joins us). Also, it's uncommon when players cash out as soon as the minimum time expires (three hours for my game). They just genuinely want to hang around and pass the time.
IMO, announcing a courtesy orbit or two is nothing, really. I would just get out of my seat and watch the game until the orbits are completed. I'll gladly lose the blinds to keep my stack safe. I know that after giving notice, the other players would be gunning for my stack like sharks. No, thank you.