Ah bells. South Carolina requires a bell or other sounding device on every bicycle. A judge on Hilton Head Island interpreted the "other sounding device" can include the riders own voice.

Bell: usually ignored. Pedestrian would turn around, stop, and look at me, causing me to strike them on two occasions.

Voice: very effective if the rider/pedestrian your overtaken understands the language you are using. I've had to learn a Spanish phrase to warn some pathway users.

Horn: the pathway parts like Moses parting the Red Sea. My theory is Americans are now conditioned to a horn being from a car. I only used a horn on my tandem and tag-along setup, as that was about 600 pounds of rolling stock on the pathway.

All that being said, causal bike riding tourist seemed to be oblivious to all manner of pathway etiquette. Riding two abreast, blocking the path with parked bikes, and not looking where they are going.