Attendees to professional conferences or expositions are usually given big ostentatious badges to wear, as proof that they are legitimate visitors to the event. Generally it's considered embarrassing to continue to wear your badge when you leave the event.

This comic is meant to portray an ironic, comedic situation where two clowns leaving the clown expo are more concerned that their badges will make them look foolish than they are that their costumes will. In technical terms, it falls under the category of "expectancy violation" or "incongruity theory."

As the other user stated it's for going to large events (corporate comicon). What they failed to mention is that it's also considered a safety issue to some extent. It also labels you as a tourist and likely shows that you are carrying spending money. It's relevant in medium sized cities, but larger ones the tourism is massive income and the locals know there will be consequences for acting out.