I recently met a genuinely funny man ... funniness beams from him.  In fact, I'd met him a few months earlier at a seminar I was running on the Gold Coast but didn't realise it.
To ensure that mobile phones don't blast my seminars (because I want people to absorb what I'm saying, not just 'attend')  I always give people the choice of turning their phones off, onto vibrate, silent or leave them on.  The only thing is:  If they choose to keep it on and it rings in the seminar, they will be asked to stand and sing "I'm a little teapot" and do the actions.
Back to my story:  He came in late to the seminar and missed the message.