In terms of Centropyge angels, while there is no way to predict what any particular fish will do, there are more things to consider than luck of the draw.
There ARE corals that they are unlikely to eat.
There ARE corals that are especially tasty to some dwarf angels.
There ARE angel species that are more likely to go after corals.
Other than possibly the yellow angels, most angels are actively after detritus and algae on the rock and other sessile invertebrates like sponges. They may have a taste for coral slime and rotting corals, not necessarily the coral. Environment and tank feeding habits are factors. An angel may be less likely to nip in a tank with seasoned live rock and the allowance of enough nutrients to feed the "rock" well. Diatoms are a favorite food. If you keep a low nutrient, sterile tank you may be more at risk.
The point is there are things you can do to slant success in your favor.