Mormons aren't alone. A reader in India writes:
Wearing special underwear is one of the five central tenets of Sikhism. There are "5K's" that Sikhs are required to wear at all times as part of their religious devotion. These symbols, along with another Sikhism tenet to never cut one's hair or shave, are probably the most visible of any religion. They are constant reminders to the believer of their faith, and greatly distinguishing articles of their faith to others. The keski is a turban. The kanga is a comb worn in the hair under the turban. The kara is an iron bracelet worn on the dominant hand. The kaccha (or kachera) are cotton underwear, similar to boxers, with a drawstring. The kirpan is a small "sword", worn under the clothes by modern Sikhs in daily life.