I hate the mandatory tip for large groups, but I see the reason for it. Years ago, when I was a waiter, I remember how things went. Large groups almost always 'forgot' to tip, or left something like $5.00. And imagine trying to serve many people all at the same time! It basically takes the whole staff to coordinate it. Six isn't such a problem, but what if there's 15 diners?

How about talking to the manager in a non-confrontational way? Tell him/her how badly things went. The damage is already done, so why not negotiate for a round of desserts? Or a round of drinks?

Depending on the tax rate where you live, it can be really easy to calculate the tip. Here in NYC, the tax is more or less 8.5%. Leaving double the tax as a tip becomes 17% on the before tax total.

An interesting development is San Francisco restaurants adding $1.00/check toward health insurance for their employees. How do you feel about that?