yes but that info isn't available that's my point. The mob/player doing the targetting needs to be targetted by you or a party member for you to get it's target. You can't run out into a field of mobs solo and know that more than one of them has you targetted.
The real issue is that there is no way to programmatically target everything around you to scan to see if any of them have targetted you. That's the only way that it could be done (that I could think of, at least) and the ability to do that reliably isn't there. You can still targetnearest I believe and you'd be able to see what that's target was, but you can't iterate through the list of everything there around you to check to see if you are a target.
It would also be useless because you have no way of knowing if you're surrounded by 2 or 12 different mobs if they have the same name and level. Script-wise there is no way to detect that murloc herd closing in on your ass, just the first one to get an auto-target from you.