I am sure LTA and TP would be happy to look into this when it gets bigger and rampant.
Personally, if the SUV is used for commercial purposes, his insurance would not cover him when there is an accident and when his passenger gets injured.
I believe that his costs is high and passengers would worry about his service dependability.
In the past, when I was in another country and their taxi service is completely messy, I always use private operators to get me out of their airports. It is a little more expensive but still worth it as I do not need to line up for hours looking for taxis.