Yes, the students should agree to be malleable by the Spiritual Master, then his success is sure. In your western part of the world, people are falsely taught not to become slavish. Everyone wants to assert his personal views and opinions, without following any authority. That is the general tendency. But although such persons claim not to be slaves, actually they are slaves to the senses. So instead of being a slave of the senses, if one voluntarily becomes the slave of Krishna, or His representative, that is good for him. This is maya, thinking that we are independent. We are slaves — every moment we are serving our senses. We are slaves to so many abominable things, to drugs, intoxication, sex, doing the most abominable things in the service of the senses. So it is not slavish when one agrees to become slave of Krishna and His representative, then this is liberated position, liberated from being slave to the senses. Yes, Srila Bhaktivinode Thakura said, My Dear Vaisnava Thakura, Spiritual Master, let me become your dog, and I shall remain at your door, and I shall guard against any nonsense persons trying to enter, and whatever food you will give me, I shall eat, and I shall remain as your dog. 

From Srila Prabhupada's letter to Sivananda — Los Angeles 11 November, 1968