remove the following line from your page template to NOT load the munchkin code:
<?php echo $mContext['endElements']; ?>
For those who want to know the details:
- the munchkin code will place a cookie on the visitor's web browser with a unique identifier (if that cookie does not yet exist)
- the munchkin code will put the cookie id into the hidden form field _mkt_trk (you cannot see this with 'view source', you'll need to use Firebug)
- during the form submit, the Cookie ID will be associated with the new email address
This process will still happen when you disable prefilling via the Landing Page's "Edit Form Settings" option. It will simply not pre-fill, but it will still pass on the cookie ID to the most recently registered email address.
Hope that clarifies.
Jep