I too have an anemone in my reef tank. Although I haven't had any casualties yet, i have had to play musical chairs with some of my zoa / sun polyps, because the BTA was stretching WAY over and stinging them - one group did die, but they were sun polyps and they grow like weeds anyways.
It isn't recommended because they will stink and kill corals if they touch them, but to my knowledge they won't go out and 'hunt' or try to kill corals, they just kill them just by random contact.