MessageBlock

MessageBlock adds a checkbox in the block special page to allow you to send a message with block's reason and duration to the user block talk page. It allows you to send the message directly from the block page.

Message and others features
To add the title and the message of this new message, just add before the import statements. Then, just change the title by the  of the message and   by the message you want.

Include duration and block reason
If you want to include either the duration or the reason of the block. Just type in the message $1 (for the reason) or $2 (for the duration). For example, your message can be : "You have been blocked for $2 because you have $1".

Auto-check the checkbox
By default, the checkbox isn't checked and have to be checked manually. If you want to check it by default, just put this before import statements :