No, they're not reef safe. If they live long enough, they will get Big, as in 24 inches from "nose" to tail tip. They're not the most graceful of creatures, and they can knock down live rock and trample corals. In the wild, they live in flat, sandy areas rather than reefs.
Whether they should be collected and sold to hobbyists is a separate question, but I wouldn't call a two foot long arthropod reef safe.