I was reading another Laserfiche post about a form being submitted even when certain required fields were not filled out. In this specific case it was because scripting was not enabled in the client's browser. The best fix for this is to add a check to see if the browser has scripting turned on or not and then making use of the <noscript> tag if necessary.
It would be great if within a Forms settings you could set whether or not to check if scripting is enabled in the client's browser. If not, allow the process admin to specify the message that should be displayed and do not allow the form to be submitted.