I would say that what is easy for a person is to remove spirits, ET's, or other kinds of external entities once all accesses have been identified and closed. It is not necessarily easy to find and close accesses.
Would you say this is similar to the common folkloric notion that if you can learn a spirit's name, then you have power over that spirit to command it?
A nameless entity is unknown, but once an entity has been named it is then classified into a logocentric structure, it is brought into the domain of the Logos, or brought into the light of consciousness, at which point consciousness can exercise will over the entity.
Whenever the topic of naming things comes up, I have to go back to Genesis where the gods brought the beasts to Adam to see what he would name them. The next statement always puzzled me: "but for Adam no helper was found." What does helping have to do with naming?
But recently it occurred to me that naming is setting boundaries which are a matter of choice. It is an exercise of the will. And we exercise will according to a purpose. A "helper" helps us accomplish our purpose. The Man had not yet discovered his purpose. So in a deep sleep (subconscious) the Man's purpose or will was separated and externalized in the form of Woman and awakening to see her was the manifestation of will into conscious awareness. His will was to gain knowledge so his externalized will helped him accomplish his purpose and gave him the forbidden fruit. Gaining knowledge is exercising choice over boundaries. The will to truth is the will to power.
The consequence of gaining knowledge (exercising the will) is to individuate which means both to become as a god as well as to die in separation.
We always have this choice before us: chaotic freedom or oppressive order. Or individuated death vs merging with the light/life. Or power vs love.
If it's a past life ego-state, for example, that the ET's have re-contacted and that past-life person had a strong relationship with one or more of the ET's, then that part may welcome the contact and cooperate with ET's without any knowledge of the conscious self and 2020 reality. The problem is that I could give you ten scenarios right off the top of my head of how these connections, agreements, permissions may be instituted by outside beings. The bottom line is, for them to gain entry, there was a 'give' and there was a 'take,' and some of those can be quite hidden or entangled.
So it sounds like you're saying a person in the present might unconsciously have a relationship with an ET or other entity as the result of a conscious agreement made in a past life. Once that is brought into present life consciousness, it can be terminated if desired.
A related scenario: If a person presently has repressed desires that are not brought into the light, could those repressed desires act as a sub personality with agency to make an agreement with an entity without the conscious awareness of the Ego?
Could we say that repressed elements of our sub-conscious are creating scenarios for us in physical reality to awaken us to their existence? (much like the externalized sub personality in the form of Eve bringing the fruit of knowledge to Adam resulting in a fall into the depths of the subconscious to become conscious of what shameful things are hiding there in the darkness under the fig leaves)