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:
   ___    __ __  ____   __  __   _  __
  / _ )  / // / / __ \ / / / /  / |/ /
 / _  | / _  / / /_/ // /_/ /  /    / 
/____/ /_//_/  \___\_\\____/  /_/|_/