In response to the comment about the wrapped/unwrapped gift. The lids lift off without unwrapping. Dan and Tripp just stores their gifts in the box to take them home.
Dan (Dan Payne), who arrives at the Christmas party unexpected, gets a present with his name on the tag. Why would there be a gift for him if he wasn't invited? He is shown unwrapping the present and reveals a Christmas sweater that he puts on. When he is leaving, the package is again wrapped. As if never opened. Tripp's present is also wrapped again too when he leaves. (But these could be just empty gift boxes.)