The original topic creator of this discussion doesn't realize something. When you warn someone, the system allows you to also send a message indicating why the person received a warning strike and this is optional. If someone is about to be banned, chances are, they have already been warned they are about to be banned.
When someone is banned, or that it comes down with someone being banned, that means that the member being banned has been disruptive to the forums and that they have been given appropriate warnings regarding the fact they they are going to be banned if they continue with their behavior. Most of everyone here probably have their forums set up where banned members cannot access any part of the forums, view images, post messages or send PM's.
It is not necessary for a banned member to read the reason for why they have been banned. I don't give anyone a reason, although, a simple 'verbal' warning sent either through a PM or through a posted message in the topic they are participating in. That's enough to get them to back off. But, if the person is being deliberately offensive, they are summarily banned permanently from the forums.
I just don't see any reason for a banned member to know why they have been banned.