Open Channeling is the way almost all mediums do mediumship, (I don't though).
Every medium, including me, meditates before a reading to become an open channel to connect with people who have passed away. They do this for clients to connect with their passed family members and friends, (and pets).
Mediums who do mediumship by "open channeling" do not control who they can connect with. They connect with whomever they feel and is the strongest presence to them at that time. But normally they bring forth departed people the client loved and knew well and give you validations you easily recognize about that person
Some mediums give great evidence/ validations but cannot pass along messages (not all loved ones have a specific "message") or allow you to ask questions of your departed loved ones. All mediums have different abilities; we are all different. I do mediumship my way naturally, I was born this way. It's like being born left-handed or right-handed ... it just is.
With a medium who 'open channels' there is no guarantee that the medium will connect with every person you want them to, or the most important ones to you. This is not good or bad, or right or wrong, it is just a fact when you choose a medium who open channels.
IMPORTANT: Since open channeling is the norm for mediums, the medium should tell you (or have on their website) upfront and honestly that they don't guarantee who comes through. There is never a legitimate reason not to.
Know that mediums don't connect with famous deceased people, Jesus, Saints, Buddha, get the lottery numbers, or things like that.
PLEASE never listen to a medium who says "your loved one must not want to talk to you", or is not around, or other departed loved ones want to talk to you more, or they're not "available" to connect with, etc. As I explained before, they most likely aren't going to connect with every loved one you want to during a reading because of the way they do mediumship because of their process. But, a medium who tries to make excuses or erroneously blame the departed loved one because the medium isn't connecting with them harms a client greatly. They're out there and some pretty well-known in their city or area.
WHAT HAPPENS WHEN EVERY MEDIUM DOES MEDIUMSHIP:
After the medium meditates, the medium feels the clear presence of the departed loved one(s) and using their different psychic senses (clairvoyance, clairaudience, claircognizance, or clairsentience), the medium will then tell the client the information they receive from the loved ones throughout the reading. I connect with one departed loved one at a time, and your loved ones know this. I have done thousands of readings.
Every departed loved one knows you are doing the reading beforehand and is very excited that you're doing a reading. They are always friendly and good to me.
The information the medium MAY receive includes: their personality, their emotions, their temperament, personal attributes or qualities, past shared experience, handyman or good/bad cook etc., how they passed (suddenly or long illness, etc), how many kids or siblings they had, special occasion or memory, messages, answers to valid questions a client has, and any validations or evidence the loved ones wants to give.
The client does not choose the validations the loved ones give, they do. Let go of any expectations and enjoy the reading. All mediums do it their own way and receive information differently including validations.
IMPORTANT NOTE:
Mediums do not have any control over departed loved ones and they do not need any. Our loved ones know exactly what they are doing. It's always about unconditional love and connection. They are ALL in "the Divine" so they are completely healed, happy and fine. Any trauma or bad stuff from their lifetime is over the moment the left this life (passed away). They can only tell the truth, and be sincerely accountable for every action they took.
Also, we are never attached to how we died after death (suicide, murder, peacefully) because we have reincarnated so many times. It's just the way in which we left that lifetime. There is no judgment, doubt, guilt, pain, etc., in the Divine. When we "die" we are surrounded by our spirit guides, Angels, and every loved one who passed before us so we could never be "lost" or stuck somewhere.
Lastly, a medium will not get every piece of information about a passed loved one in a reading. That is information overload and not possible or necessary.