Surely it would only lead to ringworms from an already present infection? Everybody had a moist nether regions, we're fungal bacteria can and will grow daily. Doesn't mean you'll have ringworm, or there'd be much more than just twenty-percent of the population with it. Showers are important, guise.
You can also get ringworm from a cat scratch, from petting a dog, and swimming in a pool. Just WALKING in a locker room can infect you.