Yes, t&c's that say that you have to be a passenger of a large air-service company. Kinda like giving great rates to anyone who joins Air France's FF program.
So if you took a ride in a jet chartered by your rich uncle and serviced by signature once, does that make you a passenger?
As I said previously, I am aware people are bending the (nearly non-existent) rules here and if National wants to pull the plug, that is their prerogative. However, they can't keep posting deals like this and expect them not to be misused. It is casting a very wide net for a very small fish.