Please keep it civil. There is no need to call people stupid.
When you are trying to bend the rules to send unsolicited messages to chat.
As to your original question
The only way to see if you, a user, is banned from a given chat, is to try sending a message to the chat. If you are banned you get a USERNOTICE with the relevant msg_id
msg_banned - You are permanently banned from talking in <channel>.