Req: a warning post

[LangTuDaTinh]

i would like to request a hack that enable for admin and mod or any members able to post a warning post. Just like an Options.

if users check it's box when they post a reply then it will add a warning message in the post.

for example.

1.a user post a reply
2. check the warning box (type of warning can be define by admin)
3. enter a message in message box (since to post a post you need to have something in your message box or you will get a error) (no hack need for this part).
4. submit a new reply.

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the reply will appear with the message from step 3, and below(or above) it will appear a warning.

the reason i do this because many of my members tend to go off topic. so this will be easier for me to give them a warning without type a waning every time.

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OR if it possible, admin and mod doesn't have to post a new reply, they just select an option from admin/mod options drop down menu...this will auto post a warning message....

thanks