Of course the danger of being in the habit of walking 'through' a propellor that is not going round, or just slowly windmilling, is that on the day when the cargo hold door needs to be checked or opened for whatever reason after the engines have been started just before pushback.......the same route might be followed by the ground crew.
They will have ear defenders on, so cannot hear shouted warnings, and cannot localise the noise as being the propellor in front of them, which of course disappears when it is rotating fast..............