Downloads will not work correctly in sub-directories of the downloads folder. I have dealt with this on a couple of "digital scrap" stores and the only fix is to move them up into the downloads folder. It does mean, where multiple designers would normally have access, you will have to change to having them upload to a temp folder and then someone trusted will have to move it into the downloads folder......

I love this
I'm not about to give them all access to the same folder because then they could delete each other's zips.
do you really want to do business with people who would do such thing, ahhhh but I have noticed in the digital scrap community these kind of things happen all of the time.....so maybe you are right to not trust them to behave like adults