Can a hypnotist helping a client speak with their higher self via hypnosis actually pave the way for an imposter to step in and mislead them? If so, how frequently does that happen in such sessions?

In the same way that the spiritually focused individuals and those interested in extraterrestrials receive special attention by the Extraterrestrial Alliance, this is true of all who use tools to engage the subconscious. This is because they understand it is a gateway to truly understand the person and their inner conflicts, as well as the intuitive reach, and that can be dangerous for them in helping people encounter and unravel various manipulations that may be underway by extraterrestrials, as well as human agents using manipulation of the mind for nefarious purposes that in turn serves the Extraterrestrial Alliance. So they will take note of such practitioners and look in on them and their doings. It is almost certain that a hypnotist helping to connect to someone's higher self will have a visit by an imposter, and this will completely derail the possibility of a benefit being obtained. There will be the semblance of useful knowledge and there will be seeming cooperation with suggestions given, but this will not bear fruit because it is not the client’s higher self being addressed, it is an imposter misdirecting the energy and intention and it will fall on deaf ears and be wasted effort. This happens again and again for many practitioners and is a travesty because the potential there is so great, as you see with your channeling, which is making valid and authentic connections to the higher selves of your clients. This, in the hands of hypnotists, is rarely achieved. In the same way that hypnosis will not allow a connection to the deep subconscious, it will not have the capability to open a gateway to the higher self either, and the latter is in fact more difficult, if one were to compare the two. So it can, in fact, be considered a futile exercise. This can only be done through bona fide authentic channeling. And this is the reason for the problems described in your recent query about the example of client higher selves giving a similar story about extraterrestrial matters to such a practitioner. This was all stage-managed information to dupe those involved, conducted by an Anunnaki psychic serving as an imposter. The mechanism is to project the thoughts into the mind of the client being hypnotized so they will speak the words. This phenomenon is directly analogous to what you see in hypnotizing a person and asking their inner spirit attachment to step forward and have a dialogue, and the spirit will indeed be brought forth with the host speaking for them to communicate their thoughts and words using the voice of the client as though the thoughts of the spirit were their own. This, of course, cannot be differentiated from fantasy or hallucination and this is the reason that the mainstream continues to deny the reality of these phenomena.