In my opinion - ONLY if they are very intelligent and knowledgeable in the area of advertising.
Today I drove by a church whose plastic letter sign said "How Guilty Are You?...worship services at 10:00".
Now, I HIGHLY doubt whether one single person who does not already regularly attend that church would come after reading that sign.
What do you think? Should churches use little quirky advertising slogans, or don't you think it matters?