Is soaking beans 24 hours unrefrigerated safe?
In fact, although the risk is low, the Penn State Extension does recommend soaking in the refrigerator, or using the quick soak method as opposed to an overnight room temperature soak:


  To be on the safe side, it would be advisable to use the quick soak method: Bring water and beans to a boil, cover and boil for 2 minutes. Remove from heat and let stand 1 hour. Drain and further cook. 


Similarly, the US Dry Bean Council recommends (emphasis added):


  A 12-hour soak in cold water before cooking helps hydrate the beans and considerably shortens cooking time. Ideally, beans should be put to soak the night before they are to be prepared and be kept in a cool place, or in the refrigerator, to avoid any fermentation taking place. Before soaking, wash them several times in cold water and remove any damaged or split beans. Discard any particles floating in the soaking water, such as small insects from the harvest, specks of dirt or other contaminants.