We're entering pretty substantial numbers of parents who grew up or at least spent their entire adult lives with cell phones and the expectation of constant communication. In fact, from my anecdotal experience, the mid-older millennial cohort is the worst at expecting immediate replies at all hours to any form of communication be it social or work.
One of the things I realize I'm grateful for in hindsight is parents who didn't grow up with that, and had no problem calling the front desk of the school if there was a legitimate emergency that needed to involve pulling me out of school. And it turns out for anything short of that, the news could wait until 4PM.
That seems like one of the easiest excuses for kids to make that is hard to argue against.
Even when I was in high school "I was responding to my mom" was the go-to excuse when caught using a cell phone. I had one teacher who would actually read what was on the screen (this was before locking your phone was common and probably lawsuit material today, but things were different) and call kids out when they were lying. The threat of having a teacher read your text messages was enough to put an end to cell phone usage in class.