Damn, Craw, you beat me to it!
This is of no surprise. It's a rare sight if you actually *do* see a guy wash his hands in a Wrigley bathroom.
Another reason aside from "holding a beer," as the article states, is that there are sometimes, especially on really crowded games, guys actually peeing in the sinks.
Baseball 101: Taking a walk with runners on 2nd and 3rd causes double plays.