I am not a SAHM, but I did take a year off for maternity leave when I gave birth to my twin girls. While I was on leave, I got called for jury duty.
I had already served for a week on a murder trial 2 years previously. It was incredibly inconvenient, but I did it and was, well, not glad to do it. Truthfully, it was one of the most depressing things I've ever seen, but I was pleased to have served and I thought we did the right thing as a jury. It was my responsibility and I took it seriously.
When I got the summons for jury duty with two nursing babies, I panicked. Yes, someone with preschool aged children can have no backup system. We didn't/don't have family in town, nor do we have the kinds of grandparents who were willing to be left alone with the twins--they were older and scared of them (one girl in particular was pretty fragile for the first 6 mos of her life). As an older mom, I didn't have friends home with young children who were willing to take in two babies. I wasn't yet networked with other moms--I went from working full time, no kids, to home all day with two babies. I found a college-aged sitter who would watch the girls for a couple of hours and that was it. I called daycares--nope, they don't take infants for short-term, undefined lengths of time. Called the court--nope, no facilities or schedule to accommodate pumping. Let me tell you--if you're nursing twins, you do not just go several hours without pumping. Called a service for in-home care and they would do the one day I was called, but would not guarantee they could provide care for then length of a trial.!