CDG sent out messages to all their cabbies as shown. Even provide a faster channel to lodge LTA complaints. Or...maybe they know their cabbies consist of those who are weak in English and cannot even file a proper complaint on their own.
Privates cars, need not necessary be PHV with decals that goes in to pick passengers. Many other private cars, some plainly hitching riders along the route they are travelling, or simply goes in to pick father mother relatives or friends.
Once CDG cabbies start to fire, most PHV drivers will start firing at taxi stands overcrowded by taxis queues, queuing until main road congested. Sooner or later....cabbies who received summons with demerits may throw back keys, and taxi stands having only the amount of taxis stated by LTA.