Am I my colleague's grammar corrector?

Several days ago as I was walking to work, I noticed a sign on a building that read: "Thank you for not smoking within 25 feet from this building." I immediately understood the sign's message, but I wondered why the sign writer had used the preposition "from" rather than the "of" that would have been expected in this sentence construction.
Since I write and try to teach writing for a living, I'm inclined to draw attention to questionable usage or grammar. But L.F., a reader from Washington, D.C., does not make her living primarily from writing or teaching others to write. She too is inclined to draw attention to such issues.
Over the past few years, she writes that she has noticed that many people, including President Barack Obama, news commentators, and well-respected academics, fail to use the article "an" before a word beginning with a vowel, such as "a issue" rather than "an issue."
"Has this grammatical rule changed?" L.F. asks. "These things drive me crazy."
She admits that she is "a bit obsessed" with the proper use of grammar.
"I've noticed in the workplace that several managers fail to use correct grammar when representing their office or their entire agency," she writes. But she observes that because poor grammar is often a reflection of upbringing, opportunity, or education, it might be too sensitive a topic to broach.
"Is it ever appropriate to provide this kind of unsolicited feedback?" she asks. "Do I need to lighten up or should I say something?"
Years ago, I wrote about how a librarian at my college who was French and learned English late in life was crushed when a student corrected her pronunciation. It wasn't the correction that crushed her, but the realization that she had been pronouncing words incorrectly for years and no one had said anything to her.
If colleagues in L.F.'s workplace are making the same grammatical errors repeatedly when they give presentations or speak to others, they could find themselves being perceived poorly. If people from outside the company are listening, they might also get the sense that the poor grammarian's colleagues don't care enough about him or her to offer a correction, or that they fear repercussions if they speak up.
The right thing is to let colleagues know when they're off in how they use grammar. They don't need to correct every incorrect usage of "I" for "me" or consider every split infinitive as a crime against humanity. But if the grammar mistake is obvious enough that it could prove embarrassing to the speaker, then the best thing to do would be to mention it to the speaker shortly after the first time you hear it. That you might show some discomfort bringing the topic up should suggest to the colleague that you're not trying to suggest that you're somehow superior to him or her because you know bad grammar when you hear it.
It could be better to suffer a little discomfort now by helping a colleague out than to wait until he or she discovers that how long the bad grammar has been going on and discovers you never set things straight. 
Jeffrey L. Seglin, author of The Simple Art of Business Etiquette: How to Rise to the Top by Playing Nice, is a lecturer in public policy and director of the communications program at Harvard's Kennedy School. He is also the administrator of www.jeffreyseglin.com, a blog focused on ethical issues. 
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