Yes, that is certainly a real phenomenon. I was speaking about 'discrimination' in it's wider sense, however, as in that there are clear rules about a cabbie's ability to reject a hail based on certain factors (like distance/time, but also race).
In reality this does happen. I've frequently been refused during 'feeding frenzies' at my local train station based on the fact that I'm not a tourist (and thus know the rules), my trip is too short, etc. In theory by rejecting a legitimate fare a cabbie is risking more than a scab would be risking (historically). Under an Uber/Lyft/etc system this problem is mitigated, probably even better than the medallion system.
In reality this does happen. I've frequently been refused during 'feeding frenzies' at my local train station based on the fact that I'm not a tourist (and thus know the rules), my trip is too short, etc. In theory by rejecting a legitimate fare a cabbie is risking more than a scab would be risking (historically). Under an Uber/Lyft/etc system this problem is mitigated, probably even better than the medallion system.