It's not exactly a "cheap trick", the technical term for the device is Dramatic Irony. And it can be used by withholding information from the audience or giving information to the audience that is withheld from the character. A master of this technique, that we all are aware of us, is Hitchcock. He'd call it his ticking clock, because he would show a bomb under a table with a ticking clock, but the characters at the table would be unaware. This led to high anxiety for the audience, even though the characters themselves were calm. Sorry to use a film analogy to make my point in a book thread, but if you knew my background you'd understand why.
I will also agree with you. If a writer abuses the use of dramatic irony, it becomes repetitive to the educated and aware reader, losing it's affect. I have the same problem with Dan Brown books. But most readers are not paying the same attention as we are and dramatic irony keeps the average reader on the hook. It's how authors sell books, so I can't fault them, but abuse of the device does aslo affect my view of them as a writer.
Damn, I tried so hard to avoid this thread till now...
