Years ago while waiting in Phoenix for our plane's late arrival, I went over on the ramp to see a large orange safety cone which was stuck and wedged between the blades in the intake of a Delta B-767's left engine. Many very small orange pieces were behind the engine. An agent had left the cone in the wrong place. This was just a large turbofan.
Two female ground agents were killed as they walked into a Metro's left prop at Newark (EWR) and into a SF-340 propellor down south. These happened at night, but daytime is no protection.
Many regional airlines operate the right engine when boarding, in order to help cool the planes etc.