Personal opinion, and the way I have always worked in the past..
Banning staff member should be allowed to remove the ban if they feel they have made a mistake.
When it comes to rejecting an appeal, the first staff member should mark it as 'pending' then, a second staff member should review the evidence and then make a decision. Not a 'chosen' staff member, but anyone who comes to that appeal first so it is not biased in any way.