Are Mandatory Gratuities Unfair? [POLL]

I was at a restaurant last night when I noticed something in small print at the bottom of the menu. This policy of automatically including a 20% gratuity on your bill for larger parties didn't affect me since it was just my fiancee and me, but I hate when restaurants do this.

It's caused numerous fights and even court challenges. Not to mention there are still a significant number of people who don't buy into the 20% standard and still go with 15%, so why should this arbitrary percentage be imposed on them? What if the service is less than stellar because the server knows their 20% is guaranteed?