You already have a nice response but, since you made a request of me, I'll carry the discussion a little further. Let's start by defining terms.
expectation: the act or state of looking forward or anticipating
flout: to show disdain, scorn, or contempt; scoff, mock, or gibe
(Definitions: Random House Dictionary)
To feel expectations about something, when something has "set up expectations," means to feel that you know what is about to come and are preparing yourself, i.e., looking forward, anticipating, for its eventual arrival.
To say that someone has flouted something is a strong statement because "to flout" is a very strong verb. To flout means to show contempt, to express scorn at worthlessness, to be derisive, ridiculing, insulting. You can see, I think, that flout is a much stronger verb than can be applied to a playful sign. So what does this question really ask (in a less than wise word choice)?
What you are really being asked--because the disappointment of expectation doesn't lead to feelings of derisiveness but rather to feelings of amusement and surprise (maybe shock)--is:
- How do the signs anticipate a particular linguistic understanding only to twist the final understanding to an unexpected reality, an unexpected meaning?
The way these signs set up an expectation that is then turned to a contrary direction is through misspellings, though these misspellings are deliberately chosen because the homonym effect can be used to crossover two meanings.
- a head: one anatomical part where the brain and facial features are housed
- ahead: to advance forward to the future
- male: the masculine gender
- mail: communications, letters, packages delivered by a postal system
Each sign uses the homonymous nature of spelling pairs. The effect is similar to the magicin's trick of slight of hand.
The sound of "a head" leads us to expect the meaning of the idiom, "get ahead," (meaning to move forward into the future) when the spelling designates that an anatomical part of a body be gotten. If we are using "flout," then the expectation of advancement is flouted by the misspelling designating not that you get to advance but that you get to get "a" "head."
Similarly, the sound of "mail" especially in context of "her daily" leads us to expect the daily delivery of postal mail, yet the spelling of "male" sabotages the idea of postal delivery and substitutes the mildly shocking though also amusing concept of a woman's daily rendezvous with a "male." Using "flout," the expectation of reliable daily postal delivery is flouted by the misspelling designating delivery of not letters and packages but delivery of males.
Intentional, deliberate misspelling for rhetorical effect is called "metaplasmus." Metaplasmus is a type of word creation, which itself is called "neologism," and is used to emphasize some element of the communication. In these communications, the emphasis is homonymous difference and is intended to amuse.
I'm not sure if you are looking for something more specific, but I can explain why these two phrases are plays on words and why people might be tricked, at first, when they read them. The dictionary definition is as follows:
A play on words: a type of joke using a word or phrase that has two meanings. It's a play on words - I suppose by calling a hairdresser's "A Cut Above'"they were hoping to give themselves a more sophisticated image.
Just as in the sample above, your first example is a play on words used by a hairdresser. When we see the phrase "Get a head," we automatically assume this means to move up or forward, as in getting ahead in life. Of course that phrase has a different spelling, but it is still the first thing we think of when we read the sign. We expect this to be the slogan for some kind of business or other opportunity which will improve our lives; instead it is a just a play on words for a place that cuts hair. The hairdresser obviously chose it because it has the implicit effect of something positive, like a promotion or an advancement. It is an interesting play on words that is easier to remember than something more nondescript.
The second example works the same way. When we read "Her daily male," our minds automatically jump to the idea of a woman who has a different male every day. Unlike the first example which implies something positive and forward-thinking, this one is a bit salacious and titillating. It implies something rather sexual in nature, when in fact, judging by the spelling, it is a sign for some kind of postal or delivery service. Again. the person who chose this name or sign is hoping to be noticed and remembered by the use of sexual innuendo. What we come to expect when we see this sign or hear this slogan might be many things, but postal services is not one of them.
Plays on words are commonly used in business to attract attention and promote memorability, two important components of marketing.