I really think Disney's "official" position is that there is no outside delivery of carts. I can see this for several reasons including not getting a cut of the action, liability if someone is hurt delivering a cart etc.
Now, with that said cart delivery companies stay below the radar by using unmarked vehicles and just pulling into the overflow lot and dropping them off. The company I used kept it even quieter by unloading in the overflow lot and driving it to my site. They looked like any other tourist taking their cart to their site.
It's possible that EZGo was making it too overt to keep Disney's lawyers happy. Maybe they were handing out cards, advertising FW delivery or something else to make Disney officially tell them that they are not "sanctioned" to deliver carts to FW.