Rule No. 1: if you have to get up early for something important (like an early- AM flight), have at least 2 means to wake you up. Just last month my husband and I left a 5:30 AM wakeup call with the front desk at our hotel so we could catch our flight hime from EDI. They didn't call. Our cheap wind-up alarm came through loud and clear. In the US I set my cell phone alarm as a backup.

I agree that that's no excuse for the hotel making a mistake- but at least they admitted it and offered compensation.