Disable auto populating of registration form fields while using the WP user integration add-on for Event Espresso 4.

wp_user_forms_disable_autofill.php

<?php
//* Please do NOT include the opening php tag, except of course if you're starting with a blank file

add_action( 'AHEE__Single_Page_Checkout___initialize_reg_step__attendee_information', 'plugin_ee_wpuser_for_attendee_no_autofill', 10 );

function plugin_ee_wpuser_for_attendee_no_autofill(){
    if (  EE_FRONT_AJAX ) {
        remove_filter( 'FHEE__EEM_Answer__get_attendee_question_answer_value__answer_value', array( 'EED_WP_Users_SPCO', 'filter_answer_for_wpuser' ), 10, 4 );
    }
    remove_filter( 'FHEE__EEM_Answer__get_attendee_question_answer_value__answer_value', array( 'EED_WP_Users_SPCO', 'filter_answer_for_wpuser' ), 10, 4 );
}