Older Daughter is in an English class where they write multiple drafts of every paper. One recent draft was "corrected" by other students. Older Daughter got a comment from the correcting student that said "Remember, don't use ; or :. They're not formal!"
Sainted Husband sent the English teacher an e-mail saying that he's published several books and served as the head of the linguistics department at a famous university and has never heard that there was anything wrong with ; or :. He got an e-mail back from the English teacher, who said that he discourages the use of ; and : because "the kids write so many run-on sentences."
Well, wouldn't it be better to teach the correct use of ; and :, instead of giving the kids the impression there's something wrong with them?
In another example of bad advice from English teachers, I was very surprised to read this post on Catherine Johnson's teaching blog, about Groucho Marx's famous elephant joke. I usually agree with Catherine, who is a founder of the kitchen table math blog, but not this time.
The Groucho joke is not an example of a misplaced modifier; there's nothing wrong with his original statement, "I shot an elephant in my pajamas." Linguists would describe it as grammatically ambiguous but pragmatically unambiguous. That's why the joke works; grammatically, it's possible that the elephant is wearing the pajamas, but pragmatically, everyone hearing the statement for the first time assumes that the speaker is wearing the pajamas.
Catherine's proposed "correction" (really, there's nothing to correct) is that the statement should have been "Wearing my pajamas, I shot an elephant." This is in no way more correct or preferable to "I shot an elephant in my pajamas."
Ambiguity is an inevitable part of natural language. It's not a bug, it's a feature! There's no getting rid of it.
Here's an example of ambiguity used by linguists: "I saw a man with a telescope." Did the speaker see a man by looking through a telescope, or was the man that he saw holding a telescope? This one is both grammatically and pragmatically ambiguous.
Here's another one: "Visiting relatives can be boring." Is the activity of visiting relatives potentially boring, or are the relatives visiting you potentially boring? Again, this one is both grammatically and pragmatically ambiguous.
For more discussion of different types of ambiguity, see this post about writing recommendations: Linguistic Humor, Ambiguous recommendations.