The win pool is much much lower than the exacta and triple pools so this happens sometimes.
I don't know of other tracks, but that is generally the case with Woodbine also. Unless of course if it is San Pail running on whom the pro bridge jumpers bet a whopping over 200 grand to win last time he ran as there was no show or place betting on him.
He won of course and the BJs collected their 5% profit but not before Windsong Geant gave them a good scare by running huge in that race by parking out another horse into a 25.4 first qtr and into a 54.4 half and losing by just 1 length to San Pail.
One BJ on another forum declared that he won't be betting San Pail again if he is running with WG next time out.