Christmas Trees: The Drunk-Monkey Decorating Secret

My mother-in-law hosts a Christmas-tree party every year. In return for food, drinks, and congeniality, she gets friends, neighbors and family to do her decorating.

An open bar + more than 40 party guests=major drunk-monkey-decorating potential, you'd think. 

And yet...

The end result comes from the involvement of many hands, but seems to reflect the thoughtful actions of actual humans. Where were the drunk monkeys?

They stayed at my house, tossing garland. I've concluded that the line between a lovely tree and a monkey tree is made from LOTS of garland.