I think we (or at least I) can put our minds at ease.
I just re-tried my E1L for rattle, and discovered that it does indeed rattle when ON... but not when off.
And in fact, it doesn't rattle easily when on:
If I turn it on and shake it, for a little while it does not rattle, and then it starts to. Also, if I turn it on and put a tiny bit of pressure on the rubber tail switch, it seems to loosen something and that makes the rattle happen.
I am not worried about it. It begins to seem like they probably all do it.
Apologies for the mistaken certainty I posted earlier.