I kept the keyboard, because it's about 10 times better than the egregious junk Apple ships, but I did pass on my concerns to MacAlly. Alas, they didn't seem to get the problem.
All of which is to say I found this blast from an ex-"Apple Genius" very validating:
ungenius - Third Party AppsIf you ever see .SIT on a file you download, send the vendor this link or a link to the Apple Genius site. If you can suggest better links please add them in the comments below. We need to get vendors like MacAlly to see the light.
... I have some special words about StuffIt Expander, though. StuffIt Expander is a scourge upon our industry and should be viciously and stubbornly squashed, mashed, neglected, and uninstalled from all encountered computers at every opportunity. With the prevalence and openness of ZIP, up to and including its status as the default archiver for OS X, and The Unarchiver there is absolutely no reason to inflict this hideous evil upon another soul. Expurgate it from your repertoire and don't hesitate to call upon the services of a licensed exorcist if necessary.