I think that it depends on a couple of things, tank size and whether there tank raised or wild caught and how they are introduced.
I have 1 mid size black and white tank raised clown which I had first, I got a large magnifca anemone which the black and white ignored. I then got a pair of wild caught clowns. The LFS said I should not put the new pair in tank with B&W or it will harass the new pair to death. I temporarily relocated the B&W to the refugium for 1 week, the wild caught clowns went straight for the anemone. After 1 week I put the B&W back I'm display tank and I don't have any issues, the B&W ignores the wild pair, the wild pair stay in there nem but are alert when the B&W swims passed. All is good though.