I guess users who will install any software without worrying about whether it is from a reliable source may need to worry about installing something which might infect their computer. Users who practice good security practices (don't install stuff if you can't verify the originator, etc., same as you do on your computer) probably don't need to worry about it. I don't need to install every piece of software out there and won't install anything that isn't from a reliable source so I'm not worried.
Personal: iPhone on AT&T
Work: BB 9650 on Sprint