I'm not kidding. In my work, ignoring items like that cause multi-million dollar losses. Remember that o-ring that failed and destroyed the space shuttle? There plenty of people on that decision that were not intimately involved with thermal cycle testing of that o-ring.
There are close to 2000 members, and I have no idea how many guests. I'd guess many of those take statements from here as fact. Some probably do not understand the physics and fomulea that describe what is happening. Some are students that are, may or will be taking physics and engineering courses. They should question statements until they are throughly convinced the information is correct.
I'm merely pointing out that everyone here that said it does not happen is technically incorrect.
I do agree though that for practical use it could be ignored.
Here is a link to some simple free body diagrams
Drawing Free-Body Diagrams