Who can request a check on an engine before boarding/takeoff?
I guess this will vary from airport and scenarios. Say if you are in a small Cessna on a little grass-strip: They will most likely always listen to you. However, In a passenger jet, on a busy airport: Things fast get a little more complicated. It is very expensive for an airliner to hold a plane, and even more to ground it. And it affects more people than it would with the Cessna scenario.

If you tell, say the flight attendant while the plane is rolling down the taxiway that you hear abnormal sounds: They will likely misinterpret you as nervous and will most likely ignore it. But if you can somehow socially convince them: It is still the captain that makes the end decision about turning around.

I don't know if this has actually happened before other than in the article mentioned in the question.



If there is something wrong about the plane: The captain will likely know well before you do. The engines have so many sensors and fail-safes that the captain will likely have the fault displayed in the cockpit before you even notice something unusual, and he will probably make the decision before you even reach a flight attendant.