The Marker Mystery

I was watching the most recent episode of Californication this morning (S03E05: Slow Happy Boys), in which Hank Moody's pal comes to visit from New Jersey. I just got done catching up on Fringe, and it is the same guy that works at the bowling alley in Fringe. Anyways, that doesn't matter. Near the end of the episode, Hank takes his friend to the airport. While saying his good-byes, something caught my eye. I really wanted them to touch on the subject, but they never did:

Why does his friend have an unopened 3-pack of sharpies in his bag?