Hey, i don't see any problem if you just want top stop by for a cup of coffee and a cigarrete, maybe a good book at any time. I do it all the time, obviously people at the restaurant know me as a frecuent visitor, this means, they've seen me there for lunch and dinner also not only for being a coffee fan. Besides, its way better to stop in a nice place that in the average starbucks, which is a shortcuit to diabetes for the amount of sugar they add in their coffees, packed full of people with their laptops and i-pods rushing for the afternoon latte enema... leave the average tip and try to be attended by the same waiter most of the times, and remember his/her name, so u'll always have a nice table whenever you need one, you'll become familiar to them for being a good customer, and a good tiper. It also works to meet interesting people :)