What is the ruling if a teacher punishes students for not standing up for him when he enters?

If you incur harm for not standing up for a teacher or an authority figure, then you must stand up to avert the harm if the standing is for the purpose of glorification and arrogance, based on the Almighty's saying: "But whoever is forced, without desiring it or exceeding due limits, there is no sin upon him. Indeed, Allah is Forgiving and Merciful." However, if standing up for him is for the purpose of righteousness, honor, and respect, then there is no harm in it, and some scholars have even deemed it recommendable.