What is Munson-split?
1.
The act of ordering foodstuff or drink -- especially appetizers and bottles of wine -- without concensus of the group, then expecting other diners to equally split the cost of the food or drink they did not consume.
I didn't want an appetizer because the meal I ordered was large, but Mike ordered the nachos anyway and tried to munson-split the cost when the check came.
Mike did this last time when he poured me a glass of wine I didn't want from his $300 bottle of cabernet he ordered. He then tried to guilt me into a munson-split of the bottle when we paid.