I just stumbled across a Holiday Chest in the SMP8 wastes, a tad northeast of the East starting post. It didn't look like it was assigned to any one player; it looked like it was just a goodie bag to anyone who finds it, so I took everything from it. For a few days or so, I'll isolate its contents in a separate storage container, and if an admin corrects me on this, I'll hand it back.
If the chest was actually named 'Holiday Chest' I believe you found a promotional chest. In that case, the items are yours to keep
Also I want to note that the chest had a sign on it that just said "Holiday Chest" or something like that. I've got all of it put in its own separate box now, and I think everything's in there right, unless I made a mistake.