[quote=@Shienvien]
As I see it, the commentbox would only be visible to three parties:

1.) The person who was barred.
2.) The person who did the barring.
3.) Mods. 

Not public. 

(EDIT: Yes, I think that letting the player know why they were barred is an [i][b]absolute must[/b][/i]. And the reason why the commentbox is post-sized, not 140 characters Twitter-style is exactly so it wouldn't be out of context, but you could quote/refer to some of the places where the player was being a disturbance, cite instances of powerplay/godmod and refusals to edit posts to remove such, state when the player last IC-posted and how long others have been waiting on them, [i]et cetera, et cetera.[/i])
[/quote]

I agree. To omit a box for a ban reason would be horrible. (I even propose that it be made mandatory.) Even if it's only two words, for example, "Illogical logic", it's far superior to having [i]no[i] reason at all. If the reason is petty, then the GM will have to make up something that will probably seem desultory or careless if an appeal is made to the ban and a moderator checks it out. It makes the appeal job for a moderator easier, whether the appeal is founded or not.

[quote=@Captain Jordan]
<Snipped quote by Shienvien>

Doesn't matter. Logic is no match for irrational thought.

You're overthinking it. 

The simple explanation is: The GM has the right to kick you from [i]their[/i] game. Boom. Done. KISS. 
[/quote]

I agree that the GM has the [i]right[/i], since they own the roleplay, but their roleplay exists on a site built in the interest of fairness, so they are subject to that site's rules. And good, fair rules include a mandatory reason for a ban. If a GM has a good reason for banning a player, they'll take the time to write at least a very short summary of said reason. Is it too much to ask of a GM to do that? I think not.