They do get an accurate placement. They race against those who show up and their end position is what it is. What are they going to do? Go through life complaining that they would have finished 2200th instead of 2201th if someone worse than them had taken the slot? What about the guy who would have pushed them to 2202th if his internet connection had not crapped out during registration? Maybe they should just accept that unless someone cheated on course, they got a fair assessment of their training and athletic ability.