NJ, please check facts before posting things as such.
Do they get a warning before they are banned:
That all depends on the reasons for them being warned or banned. I mean, if someone comes on and posts a whole bunch of child porn, then no, we aren't going to give them a slap on the wrist and tell them not to do it again, we're going to ban them. In most cases, people are warned prior to being banned, there are obvious exceptions, but those are few and far between.
Are they told why they are being banned:
There has been much questioning, for some years now as to whether the notes as to why someone is banned, is actually shown to the member. This was recently tested, and determined that no, these reasons are not in fact shown to the member in question and as such, we now send an email to explain why. Some do send PMs, and leave it a while before issuing the ban, but more often than not, it is by email. This is a new policy, and I'm sure it will take some time to get used to.
Do they get a chance to appeal:
Yes, if they want to.
Several of the moderators and myself have their email addresses public on the board, and many have put it to good use (well, mine at least, I won't speak for the others) If someone feels they've been unjustly banned, they are more than welcome to contact me, and I will always forward what ever they wish to be discussed to the others, as I have done with several since making my email available for all to use.
Do we ban who ever we want:
No, with the exception of the obvious (minors, child porn and so on) we discuss all heads ups, warnings, temp and perm bans, and these actions only take place once we've voted.