Joined: Jul 2002
Posts: 40,863
Likes: 3,116
From: Sacramento, California, USA
Bikes: Specialized Tarmac, Canyon Exceed, Specialized Transition, Ellsworth Roots, Ridley Excalibur
Club, group ride, or race? Yes, you have a duty to your fellow riders to call out hazards or, at a minimum, be smooth in avoiding them.
Some random schmoe on a MUP who happens to be behind you? Nope. Every man for himself.