Defensive Tools for Robot Submissions
The webform uses a simple but effective strategy for deflecting robot submissions from the web. It uses a combination of a "honey pot" and a "submit timer".
A honey pot is a simple trick of placing a hidden field for the email that is readable to machines but not humans. A human can't fill this field out but a machine sees no reason not to. :) A honey pot to catch the bees! If the form submits with the honey pot full, then the form is rejected.
You will notice that the submit button begins counting down from 7 as soon as you load the webform. A normal visitor will likely not every see it happen, or even if they beginning filling out the form, the timer should finish before they are ready to submit. But a robot crawling the internet (unless specially programmed to take time) will fill out a form and hit submit right away and leave not knowing the form has failed. It's not perfect, but making every submission wait 7 seconds reduces the likelihood of a robot submitting hundreds of fake leads.
If this technique ever became widely used, we would have to change it, but for the time it is a very effecting and very non-annoying robot deterrent.