I am someone who books our own air fares, knowing that if departure/arrival ports change for any reason that it is my responsibility /loss.
If someone doesn’t want this responsibility/risk then they should book flights through Seabourn. If you want a guarantee of specific places to visit, book a land holiday instead of a cruise.
I am not looking to offend but I do think that many people on these boards feel entitled to the best of all worlds. My old Nana’s saying. “ you can’t have your cake and eat it “