I've had mixed experience with bells, particularly involving pedestrians. A good number of pedestrians on the path are either listening to music or using their phone, so ringing a bell has absolutely no effect. Another large chunk react dangerously to the ringing of a bell, by either pivoting to the left directly into my path to see what that strange sound was, or abruptly jump directly into my path assuming the ring meant an imminent collision. So when it comes to pedestrians I just slow down instead and typically only ring for people with dogs and seniors as they tend to not freak out.