Continuity mistake: When George and Dr. Grace are in the cold storage room, George eats a noticeable amount of his snowball. When he hands it back to Dr. Grace to leave suddenly, it is back to being untouched.
Murdoch Ahoy - S7-E1
Continuity mistake: Amy was just rescued from a flooding hold, but when she's being helped onto the life boat her dress and hair are completely dry.
Answer: It's certainly a personal choice about using one, and probably similar to how some people refuse to wear a helmet or forego other safety equipment. Most bells and horns on bikes are not very loud and probably wouldn't be heard in busy traffic, making them mostly ineffective. Murdoch would likely still yell, even if he had a bell or horn.
raywest ★