After Night Cap worked so hard to get that espresso machine to fill a whole pot, this unicorn comes along and tries to haggle it all away. This means war.
As a player I wasn't sure what Plaid was doing. A player more clever than I likened it to the Sanford Marshmallow Experiment. Our GM's explanation is that, as a marketing guy (with a used car salesman vibe), Plaid just has to try to sell things. Here he is trying to sell Night Cap free coffee.