The Event Calendar - Permalink with starting date injected automatically.

wp-event-calendar-permalink-with-date.php

<?php
// Add this to your function.php
function please_update_slug( $data, $postarr ) {
  if($data['post_type'] == 'tribe_events') {
	    if ( !in_array( $data['post_status'], array( 'draft', 'pending', 'auto-draft' ) ) ) {
  	    $post_id = $postarr['ID'];
  		  $value = $_POST["EventStartDate"];
  		  $date = new DateTime($value);
        $data['post_name'] = sanitize_title( $data['post_title'] . '-' . $date->format('d-m-Y'));
	    }
	}
    return $data;
}
add_filter( 'wp_insert_post_data', 'please_update_slug', 99, 2 );
?>

This is great, when using the importer though you have to use $postarr['EventStartDate'], which also works when saving regularly