No, that's just a sideline, a thing people are investigating as to proof to the actual main question, whether or not this is a viral campaign sponsored by Starbucks. He quite firmly denies that.
No, because time is a consideration. If SBUX jumped on the bandwagon to sponsor it after it became a big hit. Because he could be telling the truth as at the point of the card's creation, it was just a hobby project of his and SBUX knew nothing about it.
The main question is whether he is affiliated with SBUX in any capacity, because that's a statement he made from the start and it's provably true or false.
My guess is that the truth is somewhere in between. That it was a hobby project. But that as Starbucks is a client, he figured getting some goodwill from them through it would be frosting on the cake. He didn't intend to make money directly, but obviously, if it was a success, SBUX's benefits and so does Stark's company, indirectly.
The card had been active for more than two weeks previous. My guess is that a project that is intended to be a mass-viral ad would not wait for someone to randomly submit it to HN.