An increasingly popular thing to do on Facebook is joining groups that are phrases you agree with. Whatever your cause, there is a matching group on Facebook. Many want to end the war in the Middle East, and others want to boycott Arizona because of their new immigration reform. Then there is a smaller cause: a group that was started by an angry server in a restaurant. "If you can't afford to tip 20%, don't go out to eat!"
Now don't get me wrong. In a lot of states, waitstaff makes under minimum wage and needs to make tips to survive. It's frustrating when a large group comes in and stiffs you on the tip. However, complaining about it probably won't change their ways. The best you can do is to do your job well, and hope for the best. If the problem is that you hate your job, maybe it's time to find a new one. If the problem is customers who are tightwads – well there is little you can do to get rid of them. They are always going to be out there. What good does it do to tell them to stop going out to eat, if they're going to leave a crappy tip? Fewer customers = layoffs at your restaurant. Yes, even the tightwads contribute to your employment being possible!
This group's aim is to teach people to tip better. However, the literal interpretation is valid – if you can't afford to tip 20% perhaps you should dine at home instead? I think I will – it's a hell of a lot cheaper! Hopefully everyone doesn't follow this advice, though. If they do, a lot of waitstaff will be without jobs, and I have a feeling that isn't what they expected!