i would put BIG FAT FOOT DOWN WITH A NO! if users could unzip the file. and do anything with a backup files. with that said... bye bye zip
hello .tgz it would be.
i have not ran across any actual posts that i can remember ever, of recommend editing a backup file. with general users out of the way, just leaves admins, any admin should be able to quickly find an app if not already installed to un-compress files if every need be.
there are normally some other way to upload a spreadsheet, cvs file, or like, without ever needing to deal with a backup file.
the only issue might be is "anti virus" at server level. no clue how that hooks into things.