In Harry Potter & the Deathly Hallows we see Hermione essentially erase her parents' memories of her and all they know of the magical world; she does this to protect them against retribution from Voldemort. Prior to this though, they are seen interacting with the Wizarding world here and there. This poses a question...
Are Muggle parents, spouses, siblings and family who are connected to the magical world somehow "prevented" from leaking the secret?
And if so, how?
Is it "presumed" any Muggle person closely connected to a magical child would keep the secret "out of honor", are they charmed into silence, or are their memories erased?
In the case of Harry's family, we see they outright deny his existence almost, telling friends and family he's off at some "boarding school for wayward children," or some such nonsense. This is unique to the Dursleys though; they wish to maintain the appearance of "normalcy" and purposefully separate themselves from the Wizarding world, hiding Harry somewhat begrudgingly [and seeming to do their damnedest to make him feel the outcast because of his magical heritage].
They can't be seen as the "standard" for all Muggles, though.
Considering human nature, and the amount of Muggle-born wizards and witches like Hermione, wouldn't it be likely some human would be tempted to "spill the beans" about the magical world, just to get famous for exposing it?
Note: I can buy that higher ups, such as nation leaders [hence the reference to the "Muggle Prime Minister" in some books] would know, and keep it under wraps as a governmental courtesy and not to cause a panic. This makes sense, as common folk knowing there is magic in the world would have serious repercussions from science and technology to class wars to finances. But that says nothing for the unknown numbers of regular humans who would have been exposed to magic through a family member, but not allowed to take part in it. That would likely build some resentment in some Muggles at least, which would increase the possibility of exposure.
Was this ever touched on in the books?