I wondered how people would react to the icon.

It's in that "too convenient" realm. It's really distracting, too, rather than being informative. It usually only takes you one time to find out whether or not a creature aggros, and it wouldn't even be as big an issue if they'd stop plopping high-level monsters out randomly in the middle of what seemed to be safe terrain.

Anyway, I liked the surprise of not knowing, as crazy as that sounds. I'd turn it off if you could.