RNGs (Random Number Generators) are crucial in ensuring fair play at online casinos. They are responsible for producing random and unpredictable outcomes for games, thus preventing any manipulation or bias in the results. Without RNGs, there would be a risk of unfair practices and cheating, which would greatly undermine the trust and integrity of online casinos. Therefore, RNGs play a vital role in maintaining the fairness and credibility of online casino games.