Implicature, or, "Because Everyone has Legs"

Both articles this week covered scalar implicature, specifically, when children make use of scales to extrapolate meaning, and when they don't. The most surprising result I read in Barner (2011) was that, when presented with a picture of all three animals sleeping, the children agreed the same amount to the statements "some of the animals are sleeping" and "only some of the animals are sleeping," but when the animals were specified ("(only) the cat and cow are sleeping") they were able to correctly distinguish the conditions.
The Stiller article, at first, seemed very similar, but in fact differed in an important respect: there was no conventional scale between the distinctions. However, using Grice's maxims, like a logic puzzle, the participants could figure out what was implied by a certain statement; given a face with no accessories, one with just glasses, and one with glasses and a top hat, and given the statement "my friend has glasses," both adults and children could infer that the glasses-alone figure was the friend, because if it was the glasses-and-top-hat figure, you could've just said "my friend has a top hat."

In reading these studies, I was struck with the realization that, at least in English, we lack many good ways to say things directly, and thus depend on implicature. Suppose you want a cookie. No one with good manners would directly command someone, "give me a cookie," especially if the person you're asking is in a position of power (e.g., they have cookies and you don't.) So, what are some other ways to ask?

"I would like a cookie." Oh, would you? Good for you.

"Could I have a cookie?" Yes, you could, I suppose we all could, potentially.

"Please give me a cookie." This one works, but it's only a step away from the command. The word "please" makes it a bit more polite. However, this isn't the one I would first use (would you?)

You may be familiar with this example: "Can I go to the bathroom?" I don't know, can you? Of course, only strict prescriptivist schoolteachers would insist you use "may" to ask permission. The word "please" also doesn't work here, and in fact sounds odd: "Please allow me to go to the bathroom?"
With the most commonly used statements, you're implying that you want the person to do something (give you a cookie / grant permission).

You can also see this in non-asking statements; "There's some rice in the fridge, if you want any." The implication of this statement is "eat the rice in the fridge if you want to," but a literalist would interpret it as "the rice in the fridge only exists if you want it."

Thankfully, we can use these statements in our daily lives all the time without worry, since we understand the implications behind them. When people don't understand implications, it's very frustrating (cf. the schoolteacher example). However, when we actually investigate the things we're saying, we sometimes find that they don't make sense, or are just plain incorrect, taken as they are. In the Stiller article, I was taken aback by the statement "everyone has legs, so they don't bear mention." Obviously, not everyone has legs, and, frankly it's ableist to say so. However, I also understood the implicature of the statement, which is true: "legs aren't a rare feature in people." Assuming the best intent, the authors intended that interpretation.

Often, we go off implicatures alone, for example, the adults in the Barner study who disagreed with the statement "some of the horses jumped over the log" when they all did. The adults inferred the strengthened meaning of "only some," while the children did not. Technically, some of the horses did jump over the log, but (as Grice's maxim of quantity dictates) you would provide the information that all of them did---if all of them did. While it's useful to go off implicatures in everyday life, I would posit that it's worth reexamining them sometimes to find out what we're actually saying.

I'd be very interested in hearing how people ask for things in different languages, and whether the customary phrases are direct or indirect. Also, if a more direct method of inquiry is considered rude in a language you know of, write a comment and tell me. (See what I did there?)