The following functionality allows your customers to checkout without entering an email address. You are required to enter a valid guest email that you would default to.
Put this javascript in a custom header via the “add code to the header and footer” section in your store admin's Template Configuration Settings.
<script type="text/javascript"> jQuery(function ($) { $('#customer_email').val('GUEST@EMAIL.COM').trigger('change'); }); FC.client.on('customer-email-update', function (params) { if (params.customer_email == '') { params.customer_email = 'GUEST@EMAIL.COM'; } }); FC.client.event('customer-email-update.done').prepend(function (params) { if (params.customer_email == 'GUEST@EMAIL.COM') { FC.json.anonymous_checkout_selected = true; } }); </script>