If you're sin binning someone in less than 20% of your adult games, in most leagues you really are copping out.
This is absolutely not true. I haven't sin binned a player for more than two seasons and I promise you I am not letting dissent slide.
It helps that I've been refereeing in the same adult league for 10+ years so there are players on almost every team who "know" me.
I love sin bins precisely because they are extremely effective even when they are not used. If you make it clear they are getting binned next time they chirp up, they shut up. (I would never be explicit about this, but nevertheless make it clear). Particularly effective if you've brought the skipper in, nobody want to be down to 10 men.