I disagree. While leaving a $4 tip is a little chintzy, leaving a $14 tip on a $25 bill is excessive. The whole "I took a table that could have been used by someone dining" argument makes no sense. The fact of the matter is....you sat where it was appropriate after asking. If there was a specific requirement to order lunch then you shouldn't be seated in that area.
I realize that waiters/waitresses survive on tips...but using your reasoning, the next time that you order a $4 cup of coffee at Starbucks, you should throw a $3 tip in the jar at the counter, because you didn't order a muffin as well to drive up the cost.
I would have left at least $5, and as much as $7. A 28% tip should cover the cost of bringing over drinks.