Waitresses

I have worked at a number of different resturants, including a big name fast food resturant, so I know the challenges that are associated with this job. Last night we went to a local car hop for supper. There were four adults and three children in our party. We went up to sit at the picnic tables instead of eating in the car. The table we choose had a plexiglass top and it needed wiped off. As soon as our waitress came to the table to take the drink orders, my son asked her if she would please clean the table. She said that she would. Our drinks came, table still dirty. Our food came, still dirty. So once again my son asked for it be cleaned. She finally brought out a soaking wet dish towel that looked like it need cleaning itself, and threw it in the middle of the table and looked at us like it was our responsibility to do this job. So my son, proceeded to clean the table while she stood there and watched. (It also took us a long time to get refills on our drinks.) So my question is, do you tip someone that does this? But at least we had it better than the couple at the table behind us. They sat there for at least twenty minutes and never even got her to look their way. They got up and left.