My dad likes to do "Can I call you?" which I might see later, after which he won't respond which for me essentially means I will go through "worst case scenarios" in my head over and over..
"When I see something like 'Can I call you?', it implies to me that there's something really important you need to tell me, that's too important to send over text. I know you don't mean it that way, but it's very scary to me in the absence of more information. Can you please include a reason why you'd like to talk next time you text?"
Once my folks understood that they were putting across the subtext of a death in the family, they started adding why they wanted to call!
The next time it happened, I clued my folks in to the subtext of that message for people of my generation. They were horrified and apologized profusely. They've also never done it since.