Do you cringe when you see a woman tell her kids to "shut up"?

While shopping at a Target the other day, I encountered a frazzled mom trying to tame her two little boys (looked to be around 3 or 4 years old). Wheeling them around in a cart, she repeatedly yelled “shut up!”, in a rather malicious tone when they complained that they were bored, or wanted to look at something. I can understand that she may have been stressed out, but at a glance, it seemed like she was being kind of harsh to her kids for, well, being kids. Why not a calmer “please be quiet” or a friendlier method of parental distraction to keep them amused?

Do you consider this kind of parenting behavior verbally abusive? Or is it normal for parents to snap at their kids from time to time? (They didn’t seem particularly naughty).