St. Francis of Assissi is known for a famous quote, which for all I know may be apocryphal: "Preach the gospel at all times. If necessary, use words." I was at the Jesuit college I teach at today, and I saw someone in the little snack bar on campus wearing a t-shirt that had the above quote on the back, in large enough letters that it would be visible from a pretty good distance.
Why was someone wearing this particular t-shirt in an environment littered with people who don't believe the gospel? What were those who made the t-shirt thinking it was supposed to accomplish to begin with? It involves words clearly connected with the gospel. The quote is supposed to be encouraging words related to the gospel but only in certain circumstances, presumably not ones involving casual anonymous contact with someone's back. It's not an outright contradiction, because the message isn't technically the gospel, and I suppose there might be a few extremely unlikely but possible situations in which it would be necessary to wear such a t-shirt, but doesn't it undermine the shirt's own message to wear it in a context when one will encounter nonbelievers (at least in a visible way not covered by some outer garment)?