They already have a similar policy; from the article:
Airport policy does allow drivers to refuse a fare, only if they return to the beginning of the cab line, which can mean a wait of 3 to 4 hours until their next fare.
If this policy were enforced, the problem would be solved. For whatever reason, this isn't being done.
BS. Guy pulls up with his cab and has to wait 3 to 4 hrs for a fare. I don't buy that.