It is actually a great way to advertise. There is a restauraunt that I used to go to all the time that encouraged the table top ads. some were like yours and others were just simply buisness cards stuck under the plexiglass that covered the tables. Everytime we went in there we would have to real the ad or ads at our table. It will definately get you some fairly cheap advertising...
not sure what you mean? you are paying to advertise at resturants?
Yes, My ad will be placed on the top of the tables that people will be eating at. If there are 20 tables at the restaurant then my ad will be placed on 10 tables through out the restaurant.
Seems to me this would only work if your potential clientele actually eats at the restaurant(s) you pick. So who is your primary target -- high school students in need of senior portraits (or perhaps their parents), engaged couples in need of a wedding photographer, pregnant couples soon to be in need of a baby photographer, etc? Which of these groups are likely to eat at your targeted restaurant(s)? Also, is the restaurant you have in mind going to attract sufficiently well-off people who are likely to, and can afford to, use your services? [Disclaimer: this is all conjecture, I have no direct experience with this, sorry.]
On those type of ads. you are not necessarily catering to the patrons of the restauraunt. The actual patron that read the ad will talk to their friends, etc. It is not as effective as putting up a tv ad but if the estauraunt does wel then a lot of people will see the ad. If he gets just a few customers from it that will pay the $850 for the ads.
The clientele that I'm after is all of the above. My ad will actually state something like seniors, weddings, families and so on. Before the table top company even considers putting the table tops in the restaurant they have to prove they make 2000 sales a week. The restaurant the ad will be going in will be a local Mexican restaurant so there are all types of people in and out all the time.
I've thought about all the questions you just asked and I asked them things like that as well. I see a positive outcome on this but I also wanted to see what other people thought about it as well.