Leaving a Gratuity?

Just curious, as I've never worked in a restaurant or bar: how does the server lose money if you don't tip for alcoholic drinks?

In the US if  a waitress brings you a drink and you don't tip her, she/he still has to "tip out" the bartender at the end of the night.  Some restaurants do it on a % of her tips and some do it a % of sales that waitress has done.
So if you dont tip her/him they will may end up paying a % of that drink to the bar - which equals losing money

That report also mentions that in some places if the server doesn't bring in enough tips to equal the minimum wage they get fired.  Who knows how long that takes though.  

had to comment on this after this weekend.
I took my little girl to pizza hut. The waitress was really nice and even made a smily face with the toppings for my daughers pizza. She also was really good with topping up the drinks. And I also bought a birthday cake from tescos that was next door, my lil one wanted it there, and the waitress was really nice about her having her cake in the resturant. So when the bill came, it came to just under £10,so i put £15 on the tray and she came to take it away. the manager came over to me to have a quiet word with me,she wanted to know if "i intended to leave that much because they usually dont get tips that big", I laughed and said it was fine.

had to comment on this after this weekend.
I took my little girl to pizza hut. The waitress was really nice and even made a smily face with the toppings for my daughers pizza. She also was really good with topping up the drinks. And I also bought a birthday cake from tescos that was next door, my lil one wanted it there, and the waitress was really nice about her having her cake in the resturant. So when the bill came, it came to just under £10,so i put £15 on the tray and she came to take it away. the manager came over to me to have a quiet word with me,she wanted to know if "i intended to leave that much because they usually dont get tips that big", I laughed and said it was fine.

KUDOS to you! See you got great service and showed a VERY generous amount for appreciation - funny he questioned it lol