Have you ever had to address an audience of strangers? This situation comes up for me routinely as I teach both public and private classes.  I often have to travel long distances (and deal with a lot of rigmarole) only to find many in the audience that would much rather be searching for Pokemons. I'm often conflicted between doing the job I'm being paid to do and kicking out the folks that don't want to be there. Fortunately, I've discovered some techniques to resolving this situation at the very start of my talks.