Has person who is more intelligent or from upper social cl right to silence his/her friend who is below?

I have seen this happening sometimes and experienced it also. It can happen between boys and between girls. If she for example think�s she is brighter and better in speaking than her friend she can put her hand over her mouth and keep it there for awhile and a friend who is from lower social cl accepts it and let�s it happen. Do you think it is a right way of acting, showing to one from lower level his/her place in hierarchy? And at a same time kind of indicating that she can not rise from there or make her try harder?