My take is the same - shut it down before anyone gets in or out. And
I've seen the model airplane thing more than once.

However, a discussion here some years ago drew a lot of posts from
people who get in and out all the time with the engine running. Their
arguments seemed sound but....

I concluded that for me, I will always shut it down. If you are
involved in an operation where you do it routinely and you've worked out
some reasonable procedures, go ahead. But for me, any reason I will
have for someone to get in or out is an exception, and that's when there
is a strong likehood of screwing up.

wrote:
My take on this, is that the engine should be shut down if anyone is
exiting the airplane for any reason. I think that "knowing" that the
prop is there isn't enough. People get distracted, hurried, etc.

This reminds me of a time when I was a kid and watched a friend of mine
stick his fingers into the prop swath of a model airplane. The prop cut
his finger to the bone. I asked him what happened, and he said "I guess
I just forgot it was there because I couldn't see it, and then just
reached in to adjust the idle screw"