What do you do?

Before I became a mom, I gave no thought to seeing a baby in their car seat on the top of the shopping cart. Now, it makes me cringe. Or the people who use an obviously expired car seat with no concern. What do you say to these people? I said nothing. Tonight I went to Ingles (grocery store) to get groceries. When I was walking in, their was an older woman, a grandma, walking out, she had a baby in an infant car seat, sitting on top of where a child would sit. It's dangerous, and definitely warned by car seat manufactures. Then when I was in the check out line, there was a couple checking out ahead of me. They had the infant car seat sitting inside the cart, but the car seat was super old, and i'm not talking 5 years, I'm talking at least made in the late 90's early 2000's. They also had a head rest not made with the car seat in it, an after market product. What bugged me the most was that they were buying a lot of alcohol, yet their child was using an expired car seat. I'm not saying I'm against alcohol, but when you're not providing for your child, I just can't justify that. But did I say anything to either of these people? No. I didn't. Why? I really don't know. When you see a parent/grandparent obviously misusing a car seat do you call them out? If so, what would you have said?