If there's a complaint, I do (did) what I can (could) to make the customer happy. Whatever that is -- AND comp something immediately -- such as a round of drinks or a bottle of wine, an amuse, a dessert, or a twofer for another day. Whatever it is, and whatever happened, I'm getting something on the table in front of the complaining diner as soon as possible. Even if it's saltines and gummint cheese, or an apple. Something.
As soon as I get to the table, in addition to telling the diner that food is on the way immediately, I offer information as to how long it will take to replace the dish, and if it's going to take too long discuss other options.
If the fault is the restaurant's, I admit it without grovelling and comp the offending meal -- even if I can and will fix it. If the fault is the diner's -- which happened maybe once every couple of months when I was on the line at the BF and pretty regularly at CP (because the menu was always new and could confuse people who didn't actually read it), I wouldn't comp, but would replace at no extra charge -- along with one of the extras already mentioned.
The "I'll just share my husband's" thing isn't usually a dodge. Maybe sometimes, but usually not. People who get bad or wrong food take it personally, are usually pretty upset, and their appetites suffer. The idea of waiting another 10 minutes (which is going to seem like 45 to the diner) to get what she should have had to begin with is not appealing. Not only do I not charge, I throw in dessert. If it happens a second time -- that's another story.
You've got to be hip enough to understand that some people (women perhaps more often than men) will show their displeasure by not eating. You've also got to understand that being a woman in America means having one sort or another of eating disorders thrust on you. It's complicated, but that's just how it is. Your job is to make it better, not make it more of an issue. Besides, "You knew the job was dangerous when you took it."
Easy for me to say, because I've never owned the restaurant. But charging for the soup and bread? No. Not me. Why not just call her a be-yotch and a liar to her face? Put yourself in her husband's position. If you did that to my wife, you'd never see us again. Or our friends. Or family. Or colleagues. Or anyone else I could tell. Insult the wife? Good idea. Did you put that on your business plan?
You've got to put yourself in the diner's position. That is, if (s)he's hungry -- it feels personal even though (s)he knows better. It's part of my job to take away the sting. Do I want repeat business and word of mouth or not?
How worried am I about giving away a meal to someone who tried to scam me? Not very. For one thing, once they've spilled some wine on the table cloth and got lipstick on the napkin, breathed the air-conditioning and whatnot, I'm in the hole anyway. A couple of bucks more to get a duplicate entree on the table isn't going to kill me one way or the other.
On the extras, don't get me wrong, I'm not going to comp the endless bowl of assorted gold-leafed caviars or something I'm going to run out of, I'm going to comp something that would be going to the food bank anyway. I'm nice but not nuts. The thing is to get free food on the table, NOW! And offer the diner some options immediately. They don't expect you to hand over the deed to grandma's ranch, but they do expected to be treated with R E S P E C T -- even if you're going to lose money this time. Never treat a diner as a PITA.
IMO, "Class" with a capital "C," has nothing to do with making the occasional mistake, it's how you handle them when they come along. I'd rather comp a meal and make a regular than cop an attitude and lose one. More to the point, I'd rather make the effort than not. Speaking as a diner -- Class in handling a mistake makes all the difference to me.
Just my opinion with nothing on the line (sorry, can't help myself) anymore.