Yes, I knew the story behind it. What I wonder though: Will they remember the teaching behind it or the fact that Pres. Mons wiggled his ears? Based on what I read, definetely the last one. Hence I do not see it as helpful neither effective. (Just my opinion of course).
Don't get me wrong, I am not a sour lemon . I do believe in good sense of humor, the examples you quoted about the Prophet Joseph are great. I am not questioning the humor, but the time and place.
"Decide now to make general conference a priority in your life. Decide to listen carefully and follow the teachings that are given. Listen to or read the talks more than once to better understand and follow the counsel. By doing these things, the gates of hell will not prevail against you, the powers of darkness will be dispersed from before you, and the heavens will shake for your good."
Ref. (Paul V. Johnson, "The Blessings of General Conference," Ensign, Nov. 2005, 52)