My son has been ready for school since the weekend he finished the last one, but that has little to do with whether they had just arrived back in the country from a flight, maybe the parents are limited as to their holiday entitlement or any number of other reasons.
You are making sweeping generalisations based on poppycock.
What's your problem with the dogs, should they be ready for school tommorrow also...

Actually I was going to post exactly what you did, and Cheets is too daft to even understand what you're saying, I assume he thinks you mean school holidays and they need stuff for school tomorrow, but even then that happens.
One parent reads the term start times, whacks it on calender, gets it wrong, they work it out, rushing to get stuff ready, need to get some stuff for tomorrow.
But as you suggested, if they FLEW IN, on a plane, back from holiday and the plane landed at 9pm, and the house shockingly after a two week trip has no fresh milk, bread, the kids are hungry and they just slept for 10 hours on a plan anyway.
Its just ridiculous to assume they are bad parents for taking their kids to a supermarket at 10pm.
Unless Cheets stopped to ask them why they were doing something he found so obviously(to him) wrong, then he really doesn't have a leg to stand on.
Maybe they just got back from hospital for whatever reason, or maybe its one late night driving back from family out of town, which isn't uncommon for bank holiday weekends, maybe a couple hundred different various reasons they have for the kids being awake.
What if a sick family member, friend or neighbour desparately needed some help and required something from the pharmacy or something, no, these people dared to take their kids out, what on earth is happening to society............
The truly ridiculous suggestion that good parents aim to come back from holidays at normal times, utterly ridiculous. So if you aim to fly back from the USA, leave at the right time and arrive at 10am, its all fine, no one will even possibly have jet lag, the kids are certain to sleep on the plane and therefore have a full non tired day and go to sleep at a certain time.
Of course, if the only flight out of Hawaii goes through the states and arrives at 10pm, they're bad parents for taking it?
Theres complaining about really bad things in society, crime, drug culture, chavs, pikies, violence, worsening schools and healthcare and everything else, but deciding these people are bad parents because the kids are up later than you think you'd let your kids be awake, is insane.