Next thing you know people will start demanding we remove the x button from the corner of windows because it's "too easy to close something you were working on and accidentally lose all your work."
Leave the ban button where it is, don't hide it and add delays. The last thing I want to do is have to press "Yes I am sure I want to ban this person," type in a confirmation code, validate my account, and then wait 10 seconds for a secondary confirmation period to lapse before people get banned.
If you get banned from a server, accidentally, intentionally, for a dumb reason, whatever, that is between you and the server operator, not anyone else. If they don't remember to unban you, or don't feel like unbanning you, then play on a new server. If you've been banned from all the "good" servers, develop more liberal guidelines for what qualifies as a "good" server or go find a new game.
Getting banned from places is a fact of life-- not everyone loves you.