I think its the type of force behind the yank/pull/grab that deems whether it is harmful to the child.

If its a pannicked fear stricken grab/shove to protect your child from running on to the road, then that kind of energy is relayed to the child as positive because there is no intent to hurt, the intent is to protect.

Whereas if the yank/grab/shove to prevent your child running on to the road is out of anger and frustration that they are disobeying you and putting a strain on you because you now have to react, then that creates a negative energy which i believe is felt through whatever action you use on your child.

Children are much more sensitive and in tune that we think, and i believe they feel the difference and react accordingly.

Ultimately i believe children will only behave as well as they are treated.