Block show the default VtigerCRM Confirmation box to let them decide something.
You could configure the text, the User see.
This configuration result into this in Frontend:

Enter your comment. Wiki syntax is allowed:
     __  ____   ___    ___    ____
 __ / / /_  /  / _ \  / _ \  / __/
/ // /   / /_ / ___/ / // / / _/  
\___/   /___//_/    /____/ /_/