There's two considerations that I see that would inform my approach (please note that I'm using the word “thief” as a designator, not a value judgement):
1) DQs are automatically investigated by the PIC, and may involve additional action. If the thief insists on not giving back the taken card, then I think that including that fact in your DQ report is pertinent. And while I don't have any specific knowledge of how the PIC makes decisions about further action, I suspect that a player failing to show remorse for something that is obviously not allowed is exactly the sort of situation in which further action might be warranted. I also think a store ban might be warranted even if the PIC elects not to take further action, since the player has shown a willingness to ruin everyone else's draft by stealing cards.
2) On the subject of ruining everyone else's draft, I think that drawing the thief's attention to the fact that the player receiving the 13-card pack is in a uniquely disadvantaged position within the draft is a good idea. Guilt can be a powerful motivator, and while it isn't a guarantee that the thief will do “the right thing” by returning the stolen card, I think we should try to give them that opportunity. This is doubly so since the Magic community tends to be very unforgiving of players “scumming” other players, so the risk of social ostracization (and the related opportunity to “buy back” some of that social capital) can do a lot of work for you in getting a beneficial outcome.
So, while walking through the DQ process, I would try to make it clear that the thief's choice is not just between keeping the expensive card or not, but between keeping the expensive card, ruining this other player's draft,
and potentially not being able to play Magic for the foreseeable future, or not. I think the kinds of players who are most likely to care about card value and thus commit this infraction are the kinds of players who most value their ability to keep playing Magic in sanctioned events.
Alternatively, if the player indicates that they would have wanted to drop during pack 1 and didn't know how to do that (or if they could), I would still issue the DQ but would suggest (to the players) swapping the 14-card pack they have with the 13-card pack they passed. This seems like the most efficient way to restore some integrity to the draft.
Edited Andrew Keeler (Feb. 13, 2019 12:45:27 PM)