It is because the scales are like said Animal Use Only. When a parent comes in and not paying attention to their child, and let’s say the child breaks the scale or presses tons of buttons on the scale and it can cause a huge issue for a clinic. We need a dogs weight for vaccine and medicine purposes because we use the weight of an animal to determine how much to give them.
Their weight shouldn’t matter much as long as they’re smaller than a large dog, so the issue is mostly just the kid fucking around w it. A vet tech could probably weigh a small child with the animal scale w no issues, but a child by themselves might kick it or push all the buttons at once, etc