Many of us from the previous generation learnt qura'an in that manner I.e with the stick. However this can be counterproductive as many children come to resent the teacher and the madressa. Best is to avoid using a stick.
It is important to realise that the teacher must teach and nurture the child. That also entails disciplining him. Some children learn quickly others require a slight nudge. I know personally (as a mischievous child) I required a very strong nudge in the right direction. That required many beatings from parents, teachers, elders etc. However in such a case it is important to remember the objective is to discipline the child and not to hurt him. Therefore it is better to use the hand and not a stick. This is also the order of the prophet in the case of a child that doesn't perform his Salah. Also ibn umar r.d would smack his children if they made grammatical errors while speaking. Therefore the claim that non Muslims make that the child may become traumatised is absolutely incorrect. What they think is when the drunken father returns home drunk and takes his anger out on his children. In Islam a father or teacher does it out of love not anger and more importantly while he is sober.
Hence as a mother if the teacher is smacking your child in order to discipline him, don't get offended. His intention is good. Also it'll toughen your child up. Your responsibility is to keep encouraging him and make sure he does not resent his teachers.
Also it is important to remember that if you are living in a western country it could be against the law. However as long as you keep encouraging your child it should be fine.