Unfounded Fear? Perhaps.  

You're right, that kind of stuff "never" happens.  That doesn't mean we don't think about the possibilities.  We just don't dwell on them.  When I was at PHI, I had two, yes *two* tail rotor failures that were not material failures but maintenance errors.  Fortunately, one occured just after I had set down and the other happened just after I lifted to a hover, both on offshore platforms, both would have been ugly in flight. 

Well-maintained engines don't just up and quit either, especially RR-250's.  For that matter, I can't remember the last high-side or low-side governor failure that made the rounds. But we think about it.  Again, we just don't obsess about it.  

Point being, the "single v. twin" thing just isn't much of an issue anymore for a VFR helicopter. They're both about equally risky in my book.