How safe is this workaround?

The one earlier in this thread and which I will paste below (thanks Matteo). Our network manager is not keen to use unofficial patches but we are still unable to restore 1.9 courses to 2.4 and are struggling a bit. Could anyone reassure him this won't break our Moodle? (worked fine on my local host but my local host isn't going to house 1000 users)

Hi Mary,
you need to comment out the sentence as per PHP rules. You can use /* */ or // at the very start of each line, e.g.:

        // PARAM_PATH must not be used on full OS path!
/*
        if ($sourcepath !== clean_param($sourcepath, PARAM_PATH)) {
            throw new moodle1_convert_exception('file_invalid_path', $sourcepath);
        }
*/

HTH,
Matteo