I have not called out yet, but I have talked to ETLs to be taken off the schedule for:
1. Conflict with my day job (not major--my company has a children's holiday party that my kids love, and I guess on which Saturday it would be and guessed wrong, and for some reason they didn't tell us the date as early as usual. Came in noon-8 instead of 7-3)
2. Moving to an earlier shift to go to family Christmas Eve festivities
3. Got off the schedule on a day I got a ticket to my day job's corporate suite for an NFL playoff game--the sponsor of the suite that day asked for names to be thrown into the hat of people who were fans of the team and had exceptional work years last year and my boss put me in. I could have skipped it, but would have felt super weird turning it down as such rewards pretty much never happen at my company.
So, long story short, unless something came up as an emergency with myself, husband or kids (illness, injury, etc.) I can't really think of anything that would have me calling out. If I have a problem with the schedule I've found talking to my ETL about a schedule shift works out just fine. There have been times when everything is broken at my day job and I stay later than normal, but since I usually only work 1 weekday, I can usually work around that.
What kills me on this forum is watching people angst about stuff coming up with their family or school or getting scheduled when they're not really available and they feel that their only option is to call in. Is my store unusual in that in those type of situations you can talk to your ETL or ETL HR and see if they can accommodate a switch? It seems like that would be way better for all involved, but if your leadership sucks I guess there's not much else you can do.