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:
   _  __   ____ ______   ___      __
  | |/_/  / __//_  __/  / _ \ __ / /
 _>  <   _\ \   / /    / , _// // / 
/_/|_|  /___/  /_/    /_/|_| \___/