Spinning propellers are always a hazard on ground working, such as loading or embarking the airplane. Tractor configuration leaves the rear of the plane as relatively safe working area, while a pusher is dangerous to approach from behind, while a spinning propeller may suck in things and people nearby in front of it with fatal results to both the plane and the people sucked in. Even more hazardous are unloading operations, especially mid-air, such as dropping supplies on parachute or skydiving operations, which are next to impossible with a pusher configuration airplane, especially if propellers are mounted on fuselage or sponsons.
Regarding carb heat use with Continentals, I have had more icing experiences with C-85 and O-200 engines than any other type! The Midwest has a lot of dewy mornings that are perfect for flying, but perfect for developing carb ice. I get involved with a number of post accident investigations and carb ice is a leading supposed cause for many engine failures where no hard mechanical failure or pilot mistake can be determined. Establishing the dewpoint at the time of the accident is usually number three on the list after determining if fuel was on board and selected or if there was an obvious mechanical problem.