its fine - and this is BQ race and there are critical segments which the runners could have skipped and i have confirmation from my friends that a few of the full marathon runners skipped certain segments - e.g. - between miles 18 to 23 there is no scanner to monitor if runners are completing that section
and similarly there is no scanner between miles 3 and 4.5 loop - again which the runners could have easily skipped - net net by running around 20 miles - they could have easily skipped 6 miles and get BQ easily - i don't think this is a good idea