"Taking leftover food on your plate will be consider as a Shoplifting,...

I consider that I've paid for the food, so it is mine to take home if I want! Of course, a buffet restaurant is slightly different. There you are expected to only put on your plate what you can eat and taking more than you can possibly eat just so you can take it home would certainly be fraudulent and depriving them of revenue, so they have a valid point.

Many restaurants I know will gladly wrap any uneaten food for free if you ask them - but I'm talking about the kind of restaurant where one orders from a menu and receives a set portion, not the all-you-can-eat kind!

Well I have a strong opinion on this one. No I should not but if I have food on my plate and I cannot finish it I think I should be allowed to take what is on my plate if I was already eating it. I think buffet places make very good money in the end and I do not think it would kill them to give me a piece of pizza or a piece of bread if I already paid to eat. Take care and happy mylotting to you.

so instead you are supposed to just waste it? seriously! i was at an all you can eat chinese buffet on the weekend and my mom gave me some desserts that she was too full to eat and i had taken a couple of cookies and thought about bringing them home in a napkin. (but i didn't). what are they thinking? people are paying good money for the food anyways, so what if a little extra is gone?

I think that this restaurant has a valid point. We don't get to visit all you can eat restaurants too much any more because there really aren't any around here that have a really good quality. That said, when we do visit an all you can eat restaurant I know that I've paid for all of the food that I care to eat in one sitting. I typically fix several small plates because that way I'm not wasting food.
Because of the fact that all you can eat is considered to be for that one sitting, I really think that the restaurant has a good point and is well within their appropriate rules by stating this.

The key words there are "all you can eat".

It's not "all you can fit on your plate".

So technically, if you didn't eat it, and you took it with you, it would be theft, irregardless of what they do with uneaten portions after you leave.

Not from a buffet...because you could take as much as you wanted to and eat it at home for a week! But if it's not a buffet, I'm always taking food and sneaking it into a doggy-bag. It's called a doggy-bag for a reason...so you can give it to your doggies. ha ha

I was at a wedding last Saturday night, and even though the place was all "fancy-shmancy" I still managed to sneak a big piece of steak and chicken into this ziplock bag I brought in my purse. Hey, that was dinner for my dogs when I got home. I never eat at weddings anyway, because usually I'm drinking...and why the heck would you wanna eat if you could drink instead..

It was sooooo nice to not have to cook for my dogs that night. They had wedding food for dinner

Maybe they've had previous experiences where customers still piled food (to take home, probably) on their plates given all indications that they've already finished their meal. I can only presume that this caused an undue loss on their part which required putting that sign-up. But I must admit, this is a bit far-fetched; it should have been good marketing for a restaurant for their customers to do so.

Or is this a function of culture perhaps? Where was this restaurant located and to what demographic do they usually cater to?

No not at all. With the amount of food that you can eat why would you have to bring any food home anyway. It doesn't make sense. You know if people were allowed to they would be taking a plate of food home for the next day.

My grandmother would wrap cookies in napkins and put them in her purse whenever we are at the buffet. I tell her not to but I couldn't get her to listen. I guess people do try to sneak out food but I think it's a little rude to post a sign like that for the costumers. Not a lot of people steal food and a sign isn't going to stop those who do.

I have never brought home food from a buffet place...I don't think that is right because you can take as much as you want and buffets are usually cheaper...but at any restaurant I definitely bring my food home because I can never seem to be able to finish a meal...