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