Checks if current theme has the template file for this post type

check_template.php

/**
 * check_template()
 *
 * Checks if current theme has the template file for this post type
 */
function check_template() {
    $template_name = 'single-event.php';
    $source_template_file = dirname( __FILE__ ) .'/templates/' . $template_name;
    $theme_folder = get_stylesheet_directory();
    if( !file_exists( $theme_folder . '/' . $template_name ) )
        copy( $source_template_file, $theme_folder . '/' . $template_name );
}