I was always under the impression that a backless booster seat was for older kids (like age 5+). Obviously, I don't have one. Recently, a friend came over with her 2.5 year old and I looked in the car and saw she had him in what looked like NOTHING, then I saw the small booster. He is average height and weight, probably close to my son (35 lb and 39 inches). I didn't say anything but I was kind of horrified because it just didn't look safe for a 2.5 year old! So should I say something to her? Like where did his other car seat go? Or I'm pretty sure he's too young for that?