Permanently banned users will not be kicked out of the current stream. They won’t be able to chat, but they will still be able to watch. Once they leave the stream, your shop will no longer appear on the watchfeed for them, ever.
Current stream banned users will have the same limitations as those banned from shop, but they will be able to see your future streams on the watchfeed and join/chat in those streams.
To remove a user from your blocked list, simply click the ‘-’ to the right of their username on the Banned Users tab.