This question may be moderated as unanswerable, but I am interested in opinions.
Take this scenario: Most people I know will improperly correct "The ball belongs to John and me." to "The ball belongs to John and I." The simple rule I was taught is that you remove the other party and see if the sentence makes sense. Would you say "The ball belongs to I?" No. "The ball belongs to me." Therefore, the correct wording is "The ball belongs to John and me."
If I am giving a talk to a group of people and use the correct "John and me" construct, I will cause a good portion of my audience to lose focus as they mentally (improperly) correct my grammar.
My question is this: If the purpose of language is communication, what do you do when proper grammar is a barrier to effective communication?
Do you use the proper construct, causing over half the room to stop paying attention; do you use the improper construct that most accept and lose the respect of the more educated people in the room; or do you avoid the situation altogether by wording your thoughts such that you don't need to use the distracting construct at all?