No one in their right mind would use anything but 7zip... especially trailware like WinZip and WinRar. Windows has built in Zip support if you're not in-the-know but to go out of your way to use WinZip/WinRar implies a certial level of out of date knowledge.
By default Windows handles Zip files in Explorer. Ostensibly it's fair to assume that "I don't run non-standard apps when I can avoid it" is a reasonable (if limiting) premise.
