Capturing Lead Source for Each Event

Hey Everyone,

We host several webinars every year and we would like to capture the lead source for each webinar. Here are our two options, but I would love to know if anyone has any other ideas:

• Create a hidden field for each webinar that captures the source for the lead
  • PRO: Very accurate, can be captured by hidden form element and URL params
  • CON: Creates a hidden field for every event
• Use smartlists filtered on URL parameters
  • PRO: Very simple to implement, doesnt require hidden fields
  • CON: User could potentially visit the page with multiple sources and each would be counted

Would be great to hear of some alternative methods out there or if one of these methods works well for you.

Thanks,
Erik