Would you ban someone´s partner from your restaurant if they were lying to get the food comped? Well, they certainly did!
Getting your food comped sounds so strange to me. It could be how I was raised or the fact that I'm very shy, but I would NEVER ask to get my food comped, no matter what the situation is. I'm not saying that asking for it is bad, at least not always. I get that if your food wasn't cooked properly or if you specifically asked for something not to be in it and they bring it anyway, you should say something about it. And don't get me wrong, I do that. I'm a vegetarian; you can only imagine the number of times that I ask for a dish to be prepared without meat and then it has meat. I think it happens a lot because I don't lie by saying I'm allergic to it. The thing is, I would just politely ask to get it changed, as I cannot simply remove the meat because it has already contaminated the whole food. But I don't expect the restaurant not to charge me for the dish. I would just like the food the way that I asked for it. I will still pay for it.
There was only one time in my life when I got my food comped, and no, I didn't ask for it, but I surely deserved it. A couple of years ago, I went out one night to a restaurant I had known for years. I asked for a plate of mac and cheese like I always did. The food came. I took my fork and pinched some food. I don't have it in my mouth yet when I realize that under the first layer of cheese there is a cockroach. Yes, disgusting! I didn't know how to react. I calmly called the server to the table and showed her. She apologized a million times and brought a new plate of a different meal, comped. I wanted to be nice and not run away, but I couldn't even take one bite of the new dish; I just wanted to go home. I never went back, and soon enough that place closed down.
So, to me, getting your food comped is something that the restaurant has to offer, not something you purposely ask for. If you complained about something in the food, which is fine as long as you do it calmly and with manners, and then they offered to comp your meal, then that's perfectly acceptable. But if you have already eaten most of the plate and now you have something bad to say about it to get it comped like the person from this story, then you are an entitled person who's only looking to benefit from the restaurant and have the meal for free. That is not acceptable behavior at all. So, don't be entitled and don't go around trying to get free food just for the sake of it; that's just so distasteful!