My app was called "Draw Wireless". It was a super dinky app that let people iPhones connect to each other via Bluetooth and draw on a shared whiteboard space in real time. It had a dark blue grey icon with a wireless symbol on it.
Other than the fact the icon had a dark blue background, it looked and behaved nothing like the app "Draw Something". But yet I had to redesign the icon three times and rewrite the app description four times before the reviewer felt I had distinguished enough from "Draw Something" and let it through. It took 3 freaking months.
TLDR; if your app is prominent enough then Apple will only let will go to extreme lengths to protect your app. I guess it's only if you are a small guy like these guys you need to worry about fakers.