TBH, I clip the bells off. It annoys me as much as it annoys the cats, their tags make enough noise, cats can learn to without making the bells jingle anyway, and, quite frankly, if Foot and Ula wound up outside, I'd rather they be able to sneak up on, and catch, some sort of dinner while they're on their own rather than starve. It's not like cats are incredible hunters that catch their prey every single time, and I'd rather a bird or two go to critter heaven than my cat.