A label on the mic that says 'Sing on this side' or 'You're on the wrong side of the mic'?
I don't think the performer (in my case) even considered it, as there are switches and such on the 'business' side of the mic and the other is flat.
To me it was apparent which side to sing into .. but if the singer is not paying attention, what good would the label be?
If they aren't looking for any clues to begin with they likely wouldn't notice a label.

An 'X' on the floor using tape worked here.
<grin>


I do not work here, but the benefits are still awesome
Make your sound your own!