leaky-paywall-meter-bypass.php

<?php 

add_filter( 'leaky_paywall_filter_is_restricted', 'zeen101_check_meter_bypass', 10, 3 );

function zeen101_check_meter_bypass( $is_restricted, $restriction_settings, $post_id ) {
    
    $bypass_value = 'utm_source=My+Site';
		$referrer = $_SERVER['HTTP_REFERER'];

		if ( $referrer ) {
			$check_against = $referrer;
		} else {
			$url =  "//{$_SERVER['HTTP_HOST']}{$_SERVER['REQUEST_URI']}";
			$escaped_url = htmlspecialchars( $url, ENT_QUOTES, 'UTF-8' );
			$check_against = $escaped_url;
		}

		if ( strpos( $check_against, $bypass_value ) !== false ) {
			$is_restricted = false;
		}
		
		return $is_restricted;	

}