It's not for everyone. Each should be responsible for their own actions and are at risk.
A great example was Norton Utilities, in the hands of someone who knew how to use it, it was an awesome resource, in the wrong hands it's disaster waiting to happen.
Personally I wouldn't be so inclined to be worried about trojans and viri, but more in "users error" portion of problems that arise
But as searcher61 has noted, it is good to make people aware.
-CC
EDIT: We have been lucky enough that there hasn't been any record of a malicious user/programmer "leaking" anything to truly damage or intentionally have users brick their phones.. yet.. The community has been trusting and generally helpful of one another. Which is refreshing to see in this dog eat dog world.