I am once again reminded of something the world's most famous Jewish Cowboy - Kinky Friedman - said in a book once:
Friday night was the night most people thought they were supposed to have fun. Trouble was most people didn't know what fun was or how to have it, so things usually ended up pretty ugly.
To be honest, a parking sign in the river is a reasonable result if it's the worst thing to come from thousands upon thousands of pissed idiots that descend on the waterfront at this time of year. Trouble is, it is rarely the worst.