Frank, I agree that you shouldn't feel it's unethical to accept a free meal, knowing full well you have no itention to buy anything. These companies are looking for weak willed people who for the most part are looking for something for nothing, or at best very little.
I've only been to a couple of these high pressure sales schemes, as I don't care to waste my time listening to the drivel and them nearly tieing you to the chair to make a sale.
Also, be aware that even if this meal is at a really good restaurant, you more than likely won't have a choice of entre'. More likely you'll get a chicken dish, not that that's bad, and maybe one rather inexpensive beef dish. What you get may not be on the menu even. Just a special meal the restaurant puts together for this sales pitch.
Now here's a little trick you may employ to get you out of there right after dinner. Just before the sales pitch starts, one of you, excuse yourself to go to the restroom. After using the restroom continue out of the building to your car and wait for your spouse, who should leave the table within a minute of your leaving the table. Meet in the car and go home.
Remember that these sales pitches border on unethical, so you shouldn't feel bad about not listening to their "sales pitch".
I rather enjoy butting heads with these mental midgets, however I don't feel it's worth my time anymore. Since retirement my time has become every bit as valuable as a doctor's or lawyer or even Trump's.
Karl