Entrainment is used in many contexts... one of them is physics: you put a bunch of wind-up clocks in the same room, and after a while they will all run the same way. Or put a bunch of women to interact with each other over time, and their menstrual period will synchronize.
Another experiment was done in petri dishes: two pieces of hear live heart muscles synchronized after a short time their contractions.
In network chiropractic (a version of chiropractic where they encourage the body to oscillate and repair itself) when an already oscillating patient is in the room, all other patients are more likely to begin oscillating. A number of years ago I got free care from a network chiropractor because whenever I was present, his patients had the experience of oscillation, and got better faster.
In brain-entrainment, and other sound entrainment programs they try to pull the brain to a more harmonious vibration... you start out with add, bipolar symptoms, or being hectic, and the sound of music pulls you out of that disharmonious and ineffective state to a state where you are higher functioning.
In the Sante Water products the highly energized and treated water (they say the spin was reversed and that is causing the higher energy) entrains the "normal" right-spin water over time.
Entrainment is independent of your conscious thoughts: you get entrained whether you want or not. Just imagine how you feel when you are around TV watchers, gossipers, complainers. It is not their words, it is their energy that gets to you. If you heard the same words without the energy, they wouldn't do anything to you.
News reporters are specially trained to make their vibration consistent with tragedy, drama, scarcity, suffering, so their impact can serve the Powers That Be.
Interestingly, among people the lower vibration always wins: people in the helping profession, or professional "caretakers" are always lowering their vibration to get closer to their charge.
When I am around my students, I always need to do work afterwards to restore my high vibration.
Bottom line: given that we live in the world, we need to keep around a high-vibration energy source to keep our vibration high. In addition to working on earning our Light.