I highly, highly doubt it. I can only think of two options for this:
1) Your guildie is pulling your leg and is not actually getting those items. Unless she links the actual item every time, there’s no proof she ever got them. Sure, one can use an item code to make an item link in the window, without ever having the item. Or even if she does link them, she can simply use an existing item she got ages ago and not just then and there.
2) Your guidie is on a crazy streak of luck that is ought to eventually end.
Drop rates aren’t something you can do something about in your end with the exception of magic find. A hack that’d affect them is quite unimaginable, I think loot rolls are server side, not client side things.
So, pay no mind to it is my piece of advice. Afterall, it doesn’t affect your chances of getting good loot at all, it’s not that there’s a limited amount of those items in the world