It is a usually group decision to get rid of a member of our alliance. (eg for breaking Alliance rules / principles, being unpleasant, aggressive etc)
And group decisions in our alliance will be made in the forum via a vote after sending out a circular.
However if someone is repeatedly a pain in the ass for me, distracting from the alliance current issues, by voicing innaccuracies, and giving the wrong impression of the alliance to new recruits, I may consider the alliance better off without them since it would give me more work to continually clean up after them, and my limited time and energy is better spent elsewhere.